Category: Class 9

Balbharti Maharashtra State Board Class 9 Political Science Solutions Chapter 6 International Problems Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 9 Political Science Solutions Chapter 6 International Problems

Class 9 Political Science Chapter 6 International Problems Textbook Questions and Answers

1. Choose the right option and rewrite the sentence:

Question 1.
Which among the following is an International problem?
(a) Border dispute between Maharashtra and Karnataka
(b) Kaveri water sharing question
(c) Problems of refugees
(d) Naxalism in Andhra Pradesh
Answer:
(c) Problems of refugees

Question 2.
Which among the following rights are not included in human rights?
(a) Right to work
(b) Right to information
(c) Children’s rights
(d) Equal pay for equal work
Answer:
(b) Right to information

Question 3.
Which among the following days is observed at an international level?
(a) Teachers’ Day
(b) Children’s Day
(c) Earth Day
(d) Flag Day
Answer:
(c) Earth Day

2. Explain with reasons whether the following statements are true or false:

Question 1.
It is necessary that all the nations should cooperate in order to find remedies of environmental degradation.
Answer:
True.

• The threat to the environment caused by pollution or by leakage of oil or gas does not remain restricted to one nation.
• Its effects are long term so it becomes necessary for nations to act with each other’s consent and cooperation in order to deal with these effects.

Question 2.
Sino-Indian relations are friendly.
Answer:
False.
The conflict between India and China is connected to two issues

• Border issue and
• Status of Tibet. India made several efforts to sort this border dispute by means of dialogue. But it has not met with much success.

3. Complete the following chart:

Question 1.
Human Rights

Answer:

Question 2.
Degradation of the Environment

Answer:

Question 3.
Terrorism

Answer:

4. Prepare the following concept map:

Question 1.

Answer:

5. Write your own opinion about :

Question 1.
Explain India’s position in establishing human rights.
Answer:
(i) The Preamble of the Indian Constitution contains the objectives of the Constitution.

(ii) It secures to its citizens: justice, social, economic and political; Liberty of thought, expression, belief, faith and worship; Equality of status and opportunity; and Fraternity assuring the dignity of the individual and unity and integrity of the Nation.

(iii) Fundamental Rights are assured to all the citizens of India.

(iv) In order to make these objectives effective, Fundamental Rights and Directive Principles of State Policy were incorporated in Part III and Part IV of our Constitution.

(v) The Supreme Court of India and the High Courts of all states issue Writs, such as:

• Habeas Corpus
• Mandamus
• Prohibition
• Certiorari
• Quo Warranto to protect human rights.

Question 2.
Narrate the effects of terrorism and suggest remedies to control it.
Answer:
(i) The 21st century terrorism is an organised system of violence and intimidation. There is a need to empathise, understand, cooperate and coordinate our efforts in dealing with terrorism at the national and international level.

(ii) Terrorism includes taking hostages; firing or bombing civilian localities that are undefended such as hospitals or schools, inhuman treatment to prisoners and destruction of property.

(iii) This leads to feeling of insecurity and helplessness among the people who are prone to terrorism. Their faith in social security and police protection is lowered and they may be psychologically affected.

(iv) Terrorism affects economic growth, political stability and social welfare of the people. It burdens our defence and police system as well. Hence the government cannot focus on its constructive programmes.

(v) Citizens should be alert about unattended luggage or bags at public places and be vigilant about suspicious men around them. They must immediately report to the authorities about the same.

(vi) The youth of the nation should volunteer in police and armed forces. The civilians must always cooperate with the police and government authorities to nab the terrorists.

Class 9 Political Science Chapter 6 International Problems Additional Important Questions and Answers

Choose the correct option from the given options and rewrite the statements:

Question 1.
United Nations Conference on human environment was called at Stockholm from ________.
(a) 5th to 16th June, 1972
(b) 5th to 16th July, 1972
(c) 5th to 16th June, 1971
(d) 5th to 16th July 1971
Answer:
5th to 16th June, 1972

Question 2.
The United Nations General Assembly adopted the International Covenant on Civil and Political Rights (ICCPR) in ______.
(a) 1948
(b) 1966
(c) 1964
(d) 1962
Answer:
1966

Question 3.
In 1997, the conference at Kyoto laid down the protocols for the developed countries for preventing climate change. For how many years did it come to be applied?
(a) 10 years
(b) 12 years
(c) 15 years
(d) 16 years
Answer:
15 years

Question 4.
How many Articles are there in the United Nations Declaration of Human Rights?
(a) 30
(b) 20
(c) 40
(d) 50
Answer:
30

Question 5.
When was the Declaration of the Rights of Child proclaimed?
(a) 30th November 1959
(b) 20th November 1959
(c) 20th December 1959
(d) 30th December 1959
Answer:
20th November 1959

Question 6.
When was the first Earth Day celebrated?
(a) 21st April, 1970
(b) 22nd April, 1970
(c) 23rd April, 1970
(d) 20th April, 1970
Answer:
22nd April, 1970

Question 7.
What led to the boycott of the regime in South Africa?
(a) Expatriation of Prisoners of War
(b) Racial Segregation
(c) Disobedience of the UN
(d) Asylum to international terrorists
Answer:
Racial Segregation

Question 8.
Which conference in 1997 laid down the protocols for developed countries for prevention of climatic changes?
(a) Conference at Copenhagen
(b) Conference at Amsterdam
(c) Conference at Kyoto
(d) Conference at Shimla
Answer:
Conference at Kyoto

Question 9.
Which institute/organisation is responsible for taking action against violation of human rights?
(a) Self Help Groups and NGOs
(b) Human Rights Commission
(c) Corporate bodies
(d) National Investigation Agency
Answer:
Human Rights Commission

State whether the following statements are true or false with reasons:

Question 1.
Human rights are necessary for living as a human being.
Answer:
True.
The concept of human rights has emerged from the concept of natural rights. Natural rights are those rights that we are endowed with because we are bom as human beings. In the same vein, human rights are those rights that are necessary for living as a human being.

Question 2.
The scope of human rights is limited.
Answer:
False.
The scope of human rights has in fact, broadened due to several issues of global nature like contagious diseases, the threat to environment, natural disasters, etc. Human rights today also include goals like protection of the environment and sustainable development.

Question 3.
Only internal security is threatened due to terrorist attacks.
Answer:
False.
The aim of a terrorist attack is not to endanger the geographical boundaries, but to challenge a regime in a country or refuse to acknowledge the existence of the State. This means that due to increasing terrorism, the internal security of a country is threatened in addition to its external security.

Question 4.
Once the refugees reach a safe place, they have new challenges.
Answer:
True.
Once the refugees reach a safe place, they need to find work, a place to live and other problems of a day to day nature. If the language and culture in the other nation are different, then adjusting to that poses difficulties. There is also no assurance that the people of a nation which gives shelter to the refugees will accept them.

Explain the concept:

Question 1.
Human Rights
Answer:
The concept of human rights has emerged from the concept of natural rights. Natural rights are those rights that we are endowed with because we are born as human beings. Human rights are those rights that are necessary for living as a human being and as a constituent of society.

Question 2.
Refugees
Answer:
People who have to leave their motherland against their wishes or are forced to go to other nations, seeking refuge or for security are called as refugees. People become refugees due to torture or persecution for belonging to a particular race or religion, due to war or a disaster, etc. In such situations people are forced to leave their own country and seek shelter in another country.

Question 3.
Terrorism
Answer:
Terrorism is spreading fear and terror in a society by using or threatening to use violence against common and innocent people for achieving political goals. Terrorism can be described as organised and planned violence.

Question 4.
Traditional War
Answer:
Traditional war is a conflict between two or more sovereign states. In such wars, the geographical boundaries between nations acquire importance, i.e. national security is connected with geographical boundaries.

Question 5.
Stockholm Conference 1972.
Answer:
(i) In order to discuss the immediate and long term problems related to the environment and to find solutions on them, a United Nations Conference on human environment was called at Stockholm from 5th to 16th June, 1972.

(ii) It was stressed that it is the responsibility of all nations to cooperate to overcome pollution.

(iii) The developing nations feel that the developed nations are more responsible for the decline of the environment and they should take the responsibility for stopping the decline.

(iv) Non-governmental organisations working in the field of environmental protection were also present and assumed a bigger role in the decision making process at international conferences regarding the environment.

(v) The issue of the protection of the common global wealth was raised.

(vi) A consensus emerged that it was the responsibility of all the nations to protect these resources.

(vii) It was after this conference that the United Nations created the United Nations Environment Programme (UNEP).

(viii) Many international treaties about environment were signed after this conference.

(ix) Several rules were made about the protection of environment. Environmental movements started on a large scale at national as well as at the international level.

Complete the following Chart/Concept Maps:

Question 1.

Answer:

Question 2.

Answer:

Answer the following questions in brief:

Question 1.
Which difficulties are faced by people who are forced to leave their own country?
Answer:
(i) When people of any country are forced to leave their own country as refugees, they have to face many problems.

(ii) The most important problem is to decide where to go. They have questions like will that nation give us shelter.

(iii) Secondly, they have to also take along with them other members of their family. It involves a lot of physical and emotional stress.

(iv) Apart from this, there are problems caused by natural elements like heat, rain, storms, as well as shortages of food, sickness, an enemy in pursuit, etc. In this process, many people lose their lives.

Question 2.
What was the Stockholm Conference of 1972 about?
Answer:
In order to discuss the immediate and long-term problems related to the environment and to find solutions to them, a United Nations Conference on human-environment was called at Stockholm from 5th to 16th June 1972.

Question 3.
What are the new challenges faced by refugees on reaching a safe place?
Answer:
(i) Once the refugees reach a safe place, they have new challenges. They need to find work, a place to live and other problems of a day to day nature.

(ii) If the language and culture in the other nation are different, then adjusting to that poses difficulties. There is no assurance that the people in the nation which gives shelter to the refugees will accept them.

Question 4.
What did the Environmental Conference of Rio (1992) emphasise on?
Answer:
(i) In this conference, the idea of sustainable development was stressed upon.

(ii) Different treaties regarding bio-diversity, climate change due to greenhouse gases, protection of forests, etc. were signed.

Question 5.
State the highlights of the conference on climatic change at Paris (2015).
Answer:
(i) A conference on climate change was held at Paris in November 2015.

(ii) An appeal was made in this conference that all nations should make concerted efforts to stop climate change and global warming and that the developed countries should help the developing countries to acquire the technology to achieve these goals.

Question 6.
What measures have been taken so far to save the refugees?
Answer:
(i) In 1951, some provisions were made regarding the question of refugees at the international level. One such provision was that the refugees will not be forcefully sent back to their country against their wishes.

(ii) Similarly an office of the High Commissioner of the United Nations has been established to solve their problems.

Question 7.
Give some examples of refugees.
Answer:
(i) Before the Second World War, the Jews were tortured in Germany.

(ii) Their citizenships and properties were confiscated. Due to this, the Jews became refugees.

(iii) In 1971, the people in East Pakistan turned refugees and came to India seeking refuge due to political and religious persecution.

(iv) In the last few years due to the war-like situation in Iraq and Syria, a lot of people are leaving Syria as refugees. We can cite many such example of refugees.

Question 8.
Which problems are faced by the host nation that agrees to provide shelter to the refugees?
Answer:
(i) As the number of refugees increases, the strain on the economy of the host nation increases. A shortage of essential goods is created; there may be an increase in crime or even inflation.

(ii) The locals may lose their jobs; a problem of law and order may crop up. Many such problems may emerge.

(iii) Due to these problems, many nations are not ready to give shelter to refugees and to resettle them.

Question 9.
Which steps can be taken for preservation of human rights?
Answer:
(i) If all nations safeguarded and fostered human rights, exploitation and violence would reduce. All people would be able to achieve their own development safely and securely.

(ii) Human rights could be more effectively implemented if the environment is safeguarded and if terrorism is completely wiped out.

(iii) No group of people will have to become refugees. For this, all nations have to come together, cooperate with each other, take concrete action and bring about actual change.

Question 10.
Many nations are not ready to give shelter to refugees. Why?
Answer:
Many nations are not prepared to give shelter to refugees because:

• As the number of refugees increases, the strain on the economy of the host nation increases.
• A shortage of essential goods is created; there may be an increase in crime or even inflation.
• The locals may lose their jobs; a problem of law and order may crop up.
• Many such problems may emerge.

Question 11.
The problems relating to the environment are inherently of a global nature. How?
Answer:
(i) The threat to the environment caused by pollution or by leakage of oil or gas does not remain restricted to one nation.

(ii) The visible effects of the decline of environment are extinction of species of plants and animals, decrease in the fertility of soil, water shortage, fluctuation in the proportion of rainfall, global warming, drying up of rivers and lakes, pollution of rivers and seas, incidence of newer diseases, acid rain, thinning of the ozone layer, etc.

(iii) Even if some of the effects are restricted to particular nations, these problems reach global proportions due to their long term effects, while some problems are inherently of a global nature.

Question 12.
How is terrorist war different from traditional war?
Answer:
(i) Terrorist conflict is different from traditional war.

(ii) Traditional war is a conflict between two or more sovereign states.

(iii) In such wars, the geographical boundaries between nations acquire importance, i.e. national security is connected with geographical boundaries.

(iv) On the other hand, in the case of terrorism, terrorist groups can cause violence in any part of the world from anywhere in the world.

(v) The aim of a terrorist attack is not to endanger the geographical boundaries, but to challenge a regime in a country or refuse to acknowledge the existence of the state.

Balbharti Maharashtra State Board Class 9 History Solutions Chapter 10 Changing Life 2 Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 9 History Solutions Chapter 10 Changing Life 2

Class 9 History Chapter 10 Changing Life 2 Textbook Questions and Answers

1. Choose the proper option and rewrite the completed sentences:

Question 1.
India won the cricket world cup under the captainship of ______.
(a) Sunil Gavaskar
(b) Kapil Dev
(c) Sayyad Kirmani
(d) Sandip Patil
Answer:
(b) Kapil Dev

Question 2.
The _____ language is gaining importance in India due to the process of globalisation.
(a) Punjabi
(b) French
(c) English
(d) Hindi
Answer:
(c) English

2. Complete the information in the following table:

Question 1.

Answer:

3. Give reasons for the following statements:

Question 1.
Cricket began to be played all over India, to a greater or smaller extent.
Answer:
Cricket began to be played all over India, to a greater or smaller extent because:-

• In 1983, the Indian team won the World Cup for cricket, under the captainship of Kapil Dev. It was a historic victory.
• Cricket instantly won great popularity across the country.
• In the same year, Sunil Gavaskar broke the earlier record of maximum centuries in test cricket.
• In 1985, India won the ‘Benson and Hedges’ World Championship of cricket. As a result, cricket came to be played in all States to a lesser or greater extent, but at the cost of indigenous Indian games.

Question 2.
The economy of movies is changing.
Answer:
(i) Movies in foreign languages are now translated. Even during the screening of English movies, a short Hindi translation now appears on the screen as sub-titles.

(ii) Hindi movies now compete with ‘global’ movies as they have reached every nook and comer of the world. We see a reflection of politics, social events, industry and technology in the movies.

(iii) Movies which were 3-4 hours long are now of only one or one and a half hours. Moreover, the concept of one screen and one cinema hall has given way to multiplexes.

(iv) The days of a movie running for 100 weeks in one cinema hall are over. Now one movie runs in thousands of cinema halls in India and abroad simultaneously.

(v) This development has changed the economy of movies. Production of movies has attained the status of industry.

(vi) The industry now employs crores of people. The movie industry in regional languages is also thriving.
Therefore the economy of movies is changing.

4. Answer the following questions in 25-30 words:

Question 1.
Why is it necessary to keep alive the dialects of Indian languages?
Answer:
(i) Hindi, Assamese, Bengali, Gujarati, Kannad, Kashmiri, Malayalam, Marathi, Odiya, Punjabi, Sanskrit, Tamil, Telugu, Urdu, Konkani,
Manipuri, Nepali and Sindhi are the official languages in India.
(ii) These Indian languages also have dialects, but their number is now on the decline.
(iii) Timely steps should be taken to nurture them, otherwise we will lose an important part of our heritage.
(iv) Nevertheless, Hindi, which has reached everywhere through the medium of Hindi movies, has served to unite the country by language.

Question 2.
Elaborate upon the changing scope of newspapers.
Answer:
(i) During early post-independence period, the newspapers were expected to not only give the news of daily events, but also give impetus to industry and commerce by printing advertisements.

(ii) Earlier, newspapers were black and white. With the changing times, colour printing became common.

(iii) Earlier, newspapers were thought to be the mouthpieces of the taluka or district. Now they have to face tough competition from the State level newspaper chains. But on the whole, newspapers are now becoming more active.

(iv) Their scope has enlarged to include raising funds for drought affected and flood affected people, helping meritorious students from lower income groups to go for higher education and organizing or sponsoring cultural programmes. This is how newspapers have now become an inseparable part of our lives.

Question 3.
What changes have taken place in the medium of television?
Answer:
(i) Television came to India during the post-independence period. Earlier it was black and white. Now it is coloured. Earlier it was limited to some selected programmes and fixed time-slots.

(ii) Gradually its scope was enlarged to include educational programmes, news bulletins, detailed reporting of the tours of the President and the Prime Minister.

(iii) During the telelcast of Ramayana and Mahabharat, a majority of the people used to sit glued to the television set. These serials proved the popularity of this medium. Then in 1991, CNN channel showed to the entire world a live visual reporting of the Iraq war.

(iv) In 1998, STAR (Satellite Television Asia Region) a private media house entered India, and the uninteresting, monotonous and propagandist news telecasts of the early period underwent a sea change.

(v) The language, the technique of presentation, studios equipped with the latest technology and the use of OB (outdoor broadcasting) vans have expanded the scope of Indian T.V. channels still further, and brought in transparency and variety. Now, every nook and corner of the country is connected.

Class 9 History Chapter 10 Changing Life 2 Additional Important Questions and Answers

Choose the correct option from the given options and rewrite the statements:

Question 1.
_____ won the national championship of billiards for teenagers at the age of 15.
(a) Milkha Singh
(b) Rafael Nadal
(c) Geet Sethi
(d) Prakash Padukone
Answer:
(c) Geet Sethi

Question 2.
In________ STAR (Satellite Television Asia Region) a private media house entered India.
(a) 1995
(b) 1996
(c) 1997
(d) 1998
Answer:
(d) 1998

Question 3.
In 1991, _______ showed to the entire world a live visual reporting of the Iraq War.
(a) CNN
(b) CNBC
(c) HBO
(d) NDTV
Answer:
(a) CNN

Question 4.
The Kohima Radio station had to make its broadcast in __________ languages which included English, Hindi and Naga dialects.
(a) 28
(b) 26
(c) 24
(d) 25
Answer:
(d) 25

Identify and write the wrong pair in the following sets:

Question 1.
(1) Karnam Malleshwari – Weight lifting
(ii) Sunil Gavaskar – Ace Indian Cricketer
(iii) CNN – Iraq War
(iv) Star Television – Sponsoring cultural programmes
Answer:
Wrong Pair: Star Television – Sponsoring cultural programmes

Question 2.
(i) Kapil Dev -1983 World Cup
(ii) Geet Sethi – Benson and Hedges
(iii) Karnam Malleshwari – First woman to win a medal at Olympics
(iv) Sunil Gavaskar – Maximum centuries in test cricket
Answer:
Wrong Pair: Geet Sethi – Benson and Hedges

Question 3.
(i) India won Cricket World Cup – 1983
(ii) Karnam Malleshwari won a medal at Olympics – 2000 ’
(iii) Live telecast of Iraq War -1991
(iv) Star T.V. entered India -1992
Answer:
Wrong Pair: Star T.V. entered India -1992

Do as directed:

Question 1.
Complete the following concept:

Answer:

Explain the statements with reason.

Question 1.
Hindi Movies have reached every nook and corner of the world.
Answer:
(i) In the field of entertainment, the place of Hindi movies is incomparable.
(ii) Now movies reflect contemporary themes. Film shooting locales have moved abroad.
(iii) So, viewers can now see many different places in foreign countries. Movies in foreign languages are now translated.
(iv) During the screening of English movies, a short Hindi translation now appears on the screen as sub-titles.
(v) Hindi movies now compete with ‘global’ movies as they have reached every nook and corner of the world.

Read the following passage and answer the questions:

Sports: During the pre-independence period, only a few selected games were known to people in general. Some sports persons changed this situation. This enhanced the status of both – the sports, and the sportspersons. For example, Geet Sethi achieved , global excellence in snooker, a variation of billiards. He won the national championship of billiards for teenagers at the age of 15. Later, he went on to win national and international championships. At the , global level, he won the amateur billiards competition thrice, and the professional one five times. His success made the game popular, and newspapers began to report news about billiards. Thus he made a new field available to rising sportspersons in India, It was in 1983, that the Indian team won the World , Cup for cricket, under the captainship of Kapil Dev. It was a historic victory. Cricket instantly won great , popularity across the country. In the same year, ‘Sunil Gavaskar broke the earlier record of maximum centuries in test cricket. In 1985, India won the ‘Benson and Hedges’ World Championship of cricket. As a , result, cricket came to be played in all States to a lesser or greater extent, but at the cost of indigenous Indian games. A few movies were also produced around the , theme of cricket. Live telecasts of the full five days or , one day of the matches also became available.
India had been participating in Asiad and Olympic of year 2000, Karnam Malleshwari won a medal for, weight-lifting. She was the first Indian woman to win , a medal at the Olympics. India’s representation began to rise in various Olympic games such as hockey, badminton, tennis, swimming, weightlifting and archery.

Question 1.
Which two cricket tournaments mentioned in the passage records a victory for India?
Answer:
World Cup 1983 and Benson and Hedges -1985 are the two tournaments mentioned in the passage that recorded victory for India.

Question 2.
Who was the first Indian woman to win a medal at the Olympics? Which sport did she represent?
Answer:
Karnam Malleshwari was the first Indian Women to win a medal for India at Olympic. She represented India in Women’s Weight Lifting.

Question 3.
Why do you think cricket has overshadowed other indigenous Indian Games?
Answer:
Cricket was introduced in India by the British. In the post independence period this game was mostly played by the elite. In times to come, cricket gained glamour and popularity across the nation gradually giving a setback to other indigenous games in India. Since cricketers received more professional coaching, funding and infrastructural facilities as compared to players of other games, it became inevitable that other games in India were overshadowed.

Answer the following questions in detail:

Question 1.
Do you think English has threatened our indigenous languages? How?
Answer:
(i) Hindi, which has reached everywhere through the medium of Hindi movies, has served to unite the country by language.
(ii) However, English language has been gaining ground in India due to the process of globalisation which began after 1990.
(iii) English opens the doors to multiple job opportunities. Moreover, Indians are at the forefront in learning English.
(iv) However, it is necessary to ensure that this process does not endanger the very existence of regional languages.

Question 2.
Explain the contribution of Geet Sethi and Kamam Malleswari to the field of sports.
Answer:
(i) Geet Sethi:

• Geet Sethi achieved global excellence in snooker, a variation of billiards.
• He won the national championship of billiards for teenagers at the age of 15.
• Later, he went on to win national and international championships.
• At the global level, he won the amateur billiards competition thrice, and the professional one five times.
• His success made the game popular, and newspapers began to report news about billiards.

(ii) Karnam Malleswari: At the Olympics of the year 2000, Karnam Malleswari won a medal for weightlifting. She was the first Indian woman to win a medal at the Olympics.

Balbharti Maharashtra State Board Class 9 History Solutions Chapter 6 Empowerment of Women and Other Weaker Sections Notes, Textbook Exercise Important Questions and Answers.

Maharashtra State Board Class 9 History Solutions Chapter 6 Empowerment of Women and Other Weaker Sections

Class 9 History Chapter 6 Empowerment of Women and Other Weaker Sections Textbook Questions and Answers

1. Complete the statements by choosing the proper option:

Question 1.
In 1992, a movement against drinking alcohol was started in _________.
(a) Maharashtra
(b) Gujarat
(c) Andhra Pradesh
(d) Uttarakhand
Answer:
(c) Andhra Pradesh

Question 2.
In 1975, the government of India formed the Committee on the status of women under chairmanship of ______.
(a) Dr Phulrenu Guha
(b) Uma Bharati
(c) Vasundhara Raje
(d) Pramila Dandavate
Answer:
(a) Dr Phulrenu Guha

2.B Identify the wrong pair and rewrite the corrected one:

Question 1.
(i) Saudamini Rao – Stree-Mukti Andolan Samiti
(ii) Vidya Bal – Nari Samata Manch
(iii) Pramila Dandavate – Mahila Dakshata Samiti
(iv) Jyoti Mhapsekar – Committee on the Status of Women
Answer:
Wrong Pair : Jyoti Mhapsekar – Committee on the Status of Women

3. Make a concept chart:

Question 1.
Laws related to women:
Answer:

4. Explain the concepts:

Question 1.
Alimony
Answer:
(i) A fixed amount paid to a married woman for her upkeep by the husband who has divorced her, is called alimony.
(ii) The law enacted in 1952, recognizes women’s right to alimony and their share in the father’s property. Her right to Sreedharan was recognized.

Question 2.
Minority
Answer:
(i) In any society, a group of people of a particular religion, language or race who are few in number are termed as a minority.
(ii) As there are various religions, sects, and languages in our country, we see great cultural diversity. There is variation in cultural traditions, too.

5. Explain the following statements with reasons:

Question 1.
The evolution of the women’s liberation movement.
Answer:
(i) The United Nations had declared 1975 as the International Women’s Year.

(ii) In 1975, the government of India constituted the Committee on the Status of Women and appointed Dr Phulrenu Guha as its Chairman.

(iii) A comprehensive survey was conducted on several issues such as the social position of women, their status, the consequences of the constitutional provisions made for women as also education of women and its percentage, their progress due to education, difficulties faced by working women, the position of women with respect to work /livelihood, their wages , the female-male ratio, birth and mortality rate and the role of women.

(iv) Taking into consideration this entire background, a State-wide conference for women was held in 1975 organised by the Stree-mukti Sangharsha Samiti. Women from all walks of life / regions participated in it.

(v) The Samiti published its manifesto in 1978. The policy of a struggle against discrimination on the basis of gender, caste and vama was adopted.

(vi) In 1977, groups like the Streemukti Andolan Samiti established by Soudamini Rao in Pune, Bayaja a fortnightly, as also Stree Uvach, Maitrin and Stree Anyayavirodhi Manch in Aurangabad, Mahila Dakshata Samiti in Kolhapur, Mahila Hakka in Nashik and Nari Prabodhan Manch in Latur were formed.

(vii) Anti-dowry protection committees were formed all over Maharashtra. A conference to protest against oppression of women was organised in Dhule city.

Question 2.
The Prohibition of Dowry (Amendment) Act was enacted in 1984.
Answer:
(i) Even after the enactment of the anti-dowry law, incidents like ‘Woman bums to death as sari pallu catches fire while cooking’ and ‘Woman slips into well while washing clothes, drowns and dies’ continued to be reported.
(ii) Investigations still revealed dowry to be the most frequent cause of such deaths.
(iii) The role of the police, the administration and judiciary were highlighted. This created greater awareness.
(iv) As a result, the Dowry Prohibition (Amendment) Act came into force in 1984.

Question 3.
The practice of untouchability was banned by law.
Answer:
(i) In the post-independence period, our Constitution adopted the values of freedom, equality, fraternity and social justice.
(ii) In accordance with this, the practice of untouchability was banned by law.
(iii) Untouchability was removed by the 17th paragraph of the Constitution and this class was included in the Scheduled Castes.

Question 4.
The Constitution gives cultural and educational rights to minorities.
Answer:
(i) In any society, a group of people of a particular religion, language or race who are few in number are termed a minority.

(ii) As there are various religions, sects and languages in our country, we see great cultural diversity. There is variation in cultural traditions, too.

(iii) In order to preserve their cultural traditions and develop their own language, the Constitution gives the citizens certain educational and cultural rights.

(iv) Minorities have the right to protect and conserve their language, culture and traditions.

(v) For this purpose they have the right to set up separate educational institutions.

6. Answer the following questions in 25 to 30 words:

Question 1.
Describe the Chipko movement.
Answer:
(i) The show of constructive woman power was seen during the Chipko movement in 1973.
(ii) Trees from the forests in the foothills of the Himalayas were to be cut down for commercial purposes.
(iii) Chandiprasad Bhat and Sunderlal Bahuguna had started a movement to prevent this.
(iv) Women followed the strategy of holding hands and encircling each tree.
(v) As their method consisted of protecting the tree by embracing it, the movement came to be known as the Chipko movement.
(vi) Women took part in it in large numbers. Women had a big role to play in the agricultural economy of this region.
(vii) Gaura Devi was the activist who created this awareness among the women with the help of Sudesha Devi and Bachani Devi.

Question 2.
Write a note on the Protection of Human Rights Act.
Answer:
(i) In 1993, the Protection of Human Rights Act law was enacted to prevent injustice to men and women.
(ii) The National Human Rights Commission was also formed for this purpose.
(iii) In some States, the State Human Rights Commission was also formed on the same lines.
(iv) This law which deals with collective oppression, the social conditions of divorced women, women and secure work places, played an effective role in mitigating injustices to women.

7. Answer the following question in detail:

Question 1.
Explain with examples how the united strength of women can bring about constructive changes in various fields.
Answer:
(i) Women, who have to face the brunt of scarcity of supplies and rising prices, gave a show of their strength as an organised entity in 1972.

(ii) Under the leadership of the socialist leader Mrinal Gore, women in Mumbai participated in a demonstration which came to be known as the laatne morcha (the rolling pin demonstration).

(iii) Commodities like oil, ghee, rava, maida, would become scarce just as Diwali was near at hand. Kerosene had become very expensive.

(iv) Women came together brandishing their rolling pins and took part in the demonstration.

(v) This movement met with success and the public got a glimpse of the united power of women.

(vi) Another show of constructive woman power was seen during the Chipko movement in 1973. Gaura Devi was the activist who created awareness among the women with the help of Sudesha Devi and Bachani Devi.

(vii) In 1992, three youths of Dubuganta village of Nellore district in Andhra Pradesh drowned in a lake, in a state of inebriation, and died.

(viii) At this instance, the women of the village came together and forced the closure of arrack shops.

(ix) The movement spread to the entire State and the government had to adopt a strict policy against the sale of alcohol.

(x) On 4th September 1987, Roop Kanwar, a married woman, committed sati. She did not do this of her own free will; she was coerced into doing so. Committing sati, glorifying the practice of sati were all illegal acts.

(xi) The women activists and journalists, Meena Menon, Geeta Seshu, Sujata Anandan, Anu Joseph and Kalpana Sharma investigated the case. In 1998, the government passed the Sati (Prevention) Act with very stringent provisions.

Class 9 History Chapter 6 Empowerment of Women and Other Weaker Sections Additional Important Questions and Answers

Choose the correct option from the given options and rewrite the statements:

Question 1.
Under the leadership of the socialist leader ______ women in Mumbai participated in a demonstration which came to be known as the Laatne Morcha.
(a) GauraDevi
(b) Dr Phulrenu Guha
(c) Meena Menon
(d) Mrinal Gore
Answer:
(d) Mrinal Gore

Question 2.
Vinoba Bhave made use of women power in the _____.
(a) Bhoodan Movement
(b) Chipko Movement
(c) Laatne Morcha
(d) Anti-liquor movement
Answer:
(a) Bhoodan Movement

Question 3.
Women activists associated with the Chipko movement ________.
(a) Sucheta Kripalani, Nandini Satpathy and Jayalalitha
(b) Dr Phulrenu Guha, Uma Bharati and Vasundhara Raje
(c) Gaura Devi, Sudesha Devi and Bachani Devi
(d) Dr Phulrenu Guha, Meena Menon and Mrinal Gore
Answer:
(c) Gaura Devi, Sudesha Devi and Bachani Devi

Question 4.
The Chipko movement was started by ______.
(a) Chandiprasad Bhat and Sunderlal Bahuguna
(b) Sudesha Devi and Bachani Devi
(c) Vinoba Bhave and Mahatma Gandhi
(d) Meena Menon and Mrinal Gore
Answer:
(a) Chandiprasad Bhat and Sunderlal Bahuguna

Question 5.
The United Nations had declared as _____ the International Women’s Year.
(a) 1992
(b) 2000
(c) 1975
(d) 1988
Answer:
(c) 1975

Question 6.
A collection of songs called Streemuktichi Lalkari, a street play called Mulgi Jhaali Ho are written by ______.
(a) Vidya Bal
(b) Pramila Dandavate
(c) Sujata Anandan
(d) Jyoti Mhapsekar
Answer:
(d) Jyoti Mhapsekar

Question 7.
A State-wide conference for women was held in 1975 organised by the _______.
(a) Samajwadi Mahila Sabha.
(b) Stree-mukti Sangharsha Samiti.
(c) Nari Prabodhan Manch.
(d) Stree Anyayavirodhi Manch.
Answer:
(b) Stree-mukti Sangharsha Samiti.

Question 8.
Census is conducted in India every _______.
(a) 5 years
(b) 10 years
(c) 15 years
(d) 20 years
Answer:
(b) 10 years

Identify and write the wrong pair in the following sets:

Question 1.
(i) Vinoba Bhave – Bhoodan Movement
(ii) Chandiprasad Bhat and Sunderlal Bahuguna – Chipko movement
(iii) Dr Phulrenu Guha – Laatne Morcha
(iv) Shah Bano Begum – Right to alimony
Answer:
Wrong Pair: Dr Phulrenu Guha – Laatne Morcha

Question 2.
(i) Stree Anyayavirodhi Manch – Aurangabad
(ii) Mahila Dakshata Samiti – Pune
(iii) Mahila Hakka – Nashik
(iv) Nari Prabodhan Manch – Latur
Answer:
Wrong Pair : Mahila Dakshata Samiti – Pune

Question 3.
(i) Stree-mukti Andolan Samiti – Soudamini Rao
(ii) Mahila Dakshata Samiti – Phulrenu Guha
(iii) Milun Saryajani – Vidya Bal
(iv) Laatne Morcha – Mrinal Gore
Answer:
Wrong Pair: Mahila Dakshata Samiti – Phulrenu Guha

Question 4.
(i) Streemuktichi Lalkari – Collection of songs
(ii) Mulgi Jhaali Ho – Periodical
(iii) Bayaja – fortmighty
(iv) Sitama Katha – Story
Answer:
Wrong Pair : Mulgi Jhaali Ho – Periodical

Do as directed
Make a concept chart:

Question 1.
Roop Kanwar Sati Case.
Answer:

Question 2.
List at least five Women Chief Ministers in India:
Answer:

• Sucheta Kriplani (Uttar Pradesh)
• Nandini Satpathy (Odisha)
• Jayalalitha (Tamil Nadu)
• Mayawati (Uttar Pradesh)
• Vasundhara Raje (Rajasthan)
• Mamata Banerjee (West Bengal)
• Rabdi Devi (Bihar)
• Anandiben Patel (Gujarat)
• Sheila Dixit (Delhi)
• Mehbooba Mufti Sayeed (Jammu & Kashmir)
• Uma Bharati (Madhya Pradesh)
• Rajendra Kaur Bhattal (Punjab)
• Sushma Swaraj (Delhi)
• Shashikala Kakodkar (Goa)
• Sayeeda Anwar Taimur (Assam)
• Janaki Ramachandran (Tamil Nadu), are all women who have led their States as Chief Ministers.

Complete the following chart:

Question 1.

Answer:

Write short notes on:

Question 1.
International Women’s Day
Answer:
(i) A demonstration was held in New York on 8 March 1857.

(ii) It was the first demonstration by working women and its demands were for fewer working hours, proper remuneration, provision of creches, etc.

(iii) On 8 March 1909 women went on strike for the very same demands. That is why, this day was declared as the Women’s Struggle Day at the Women’s Socialist International, a conference held in Denmark.

(iv) The year 1975 was observed as the International Women’s Year and in 1977, 8 March was declared as International Women’s Day by a resolution passed in the General Assembly of the United Nations.

(v) The three aspects of this programme were peace, development and equality between men and women.

Question 2.
Family Courts
Answer:
(i) Family courts were established to resolve conflicts arising out of differences within marriage and domestic problems as well as issues such as alimony, single parenthood, separation, care of children and ownership which are all related to the family situation.
(ii) These family courts give priority to mutual understanding over witnesses and evidence and to counsellors over lawyers.
(iii) Emphasis is on resolving issues quickly but justly.

Question 3.
Reservation for Women
Answer:
(i) The 73rd and 74th amendments to the Constitution provide for reservation of one-third of the seats for women in Gram Panchayats, Panchayat Samitis, Zilla Parishads, municipalities and municipal corporations as well as for the posts of Sarpanch, Chairman and Mayor.
(ii) Maharashtra and 15 other states have reserved 50% seats for women.
(iii) This provision provides women the opportunity to participate in the business of the community.

Question 4.
Scheduled Tribes
Answer:
(i) The Scheduled Tribes or Adivasis who live in remote parts of the country face several difficulties.

(ii) As they have lived far away from the progress made in modem times, they are economically and socially backward.

(iii) Even though their conditions have seen some improvement in recent times, they do not have any means of livelihood other than agriculture and forest produce.

(iv) Modem farming implements have not yet reached them. Hence, their income from agriculture is very small. Besides, their fields are on hillsides and not fertile.

(v) They are malnourished due to insufficient and poor quality of diet.

(vi) Adivasis in remote areas find it difficult to get medical attention in time. For all these reasons, there is a need to give special protection to Adivasis.

(vii) In the Indian Constitution, Adivasis have been enumerated as Scheduled Tribes. They are given representation in law boards, education, government service, etc.

Question 5.
8th March was declared as International Women’s Day.
Answer:
(i) A demonstration was held in New York on 8 March, 1857. It was the first demonstration by working women and its demands were for fewer working hours, proper remuneration, provision of creches, etc.

(ii) On 8 March 1909 women went on strike for the very same demands. That is why, this day was declared as the Women’s Struggle Day at the Women’s Socialist International, a conference held in Denmark.

(iii) The year 1975 was observed as the International Women’s Year and in 1977, 8 March was declared as International Women’s Day by a resolution passed in the General Assembly of the United Nations.

Question 6.
The ‘Muslim Women’s Act’ (Protection of rights on divorce) was passed by Parliament.
Answer:
(i) A fixed amount paid to a married woman for her upkeep by the husband who has divorced her, is called alimony.

(ii) In the case of Mohammad Ahmed Khan vs Shah Bano Begum, the Supreme Court gave the verdict that Shah Bano Begum had the right to alimony.

(iii) However, religious organisations protested vociferously against the verdict.

(iv) As a result, the ‘Muslim Women’s Act’ (Protection of rights on divorce) was passed by Parliament.

Question 7.
In 1998, the government passed the Sati (Prevention) Act with very stringent provisions.
Answer:
(i) On 4th September 1987, Roop Kanwar, a married woman, committed sati. She did not do this of her own free will; she was coerced into doing so.

(ii) Committing Sati, glorifying the practice of Sati were all illegal acts.

(iii) The women activists and journalists, Meena Menon, Geeta Seshu, Sujata Anandan, Anu Joseph and Kalpana Sharma investigated the case.

(iv) So in 1998, the government passed the Sati (Prevention) Act with very stringent provisions.

Read the passage and answer the questions:

Passage I

International Women’s year: The United Nations ! had declared 1975 as the International Women’s Year. The three aspects of this programme were peace, development and equality between men and women. In 1975, the government of India constituted the Committee on the Status of Women and appointed Dr Phulrenu Guha as its Chairman. A comprehensive survey was conducted of several issues such as the social position of women, their status, the consequences of the constitutional provisions made for Women as also education of women and its percentage, their progress due to education, difficulties faced by working women, the position of women with respect to work/livelihood, their wages (relative to men’s wages), the female-male ratio, birth and mortality rates and the role of women.
Taking into consideration this entire background, State-wide conference for women was held in 1975 organised by the stree-mukti Sangharsha Samiti. Women from all walks of life/regions participated in it. The Samiti published its manifesto in 1978. The Samiti published its manifesto discrimination on the basis of gender, caste and vama was adopted.
This gave rise to a collection of songs called Streemuktichi Lalkari, a street play called Mulgi Jhali Ho by Jyoti Mhapsekar and a periodical called Prerak Lalkari which became their mouthpiece and other such programmes. In 1977, groups like the Streemukti Andolan Samiti established by Soudamini Rao in Pune, Bayaja a fortnightly, as also Stree Uvach, Maitrin and Stree Anyayavirodhi Manch in Aurangabad, Mahila Dakshata Samiti in Kolhapur, Mahila Hakka in Nashik and Nari Prabodhan Manch in Latur were formed. Anti-dowry protection committees were formed all over Maharashtra. A conference to protest against oppression of women was organised in Dhule City.

Question 1.
Prepare a time line of the highlights mentioned in the passages.
Ans:
Timeline of the Highlights of the passage

• 1975 – UN declared International Women’s Day Committee on the Status of women was appointed.
• 1975 – Stree Mukti Sangharsha Samiti was organised.
• 1978 – Stree Mukti Sangharsha Samiti published a Manifesto
• 1977 – Stree Mukti Andolan Samiti was established by Soudamini Rao.

Question 2.
State the issues on which a survey was conducted by the committee on the status of women.
Ans:
The Committee on Status of Women appointed under the chairmanship of Dr. Phulrenu Guha made a comprehensive survey over several issues:

• Social position of women and their status.
• Consequences of the constitutional provision made for women.
• Education of women and it’s a percentage.
• Their progress due to education.
• Difficulties faced by working women with respect to work, livelihood, and wages.
• Female – male ratio.
• Birth and mortality rates.
• Role of women.

Question 3.
Name any two women who according to you managed to break the norms of the Indian Society and came up as icons of woman power.
Ans:
(i) Mrinal Gore
(ii) Gaura Devi

Passage II

Vidya Bal’s periodicals, Nari Samata Manch, and Milun Saryajani, as also the work ofthe Samajwadi Mahila Sabha and the Krantikari Mahila Sanghatana were of great help in dealling with women’s issues. The Employment Guarantee Scheme in Maharashtra also helped to empower women. Pramila Dandavate established the Mahila Dakshata Samiti in Delhi in 1976. Branches of the Samiti came up in the States of Andhra Pradesh, Tamil Nadu, Kerala, Odisha, Madhya Pradesh, Uttar Pradesh and Punjab. The Communist Party established the Akhil Bharatiya Janavadi Mahila Sanghatana in 1980. Efforts were made to start branches of this Organisation in all parts of India. The Sanghatana started a struggle against issues like dowry, female foeticide, domestic abuse, Research on women’s issues was undertaken at various levels. Women’s Studies Centres were started at the first women’s university, Mumbai and at Tata Institute of Social Sciences, Mumbai, Savitribai Phule Pune University and Shivaji University, Kolhapur. These Centres played an important role in critical analysis and in developing a vision on women’s issues.

Question 1.
State the role of Pramila Dandavate and Vidhya Bal in women’s upliftment.
Answer:
(i) Pramila Dandavate established Mahila Dakshata Samiti in Delhi in 1976.
(ii) Vidya Bal published periodicals like ’Nari Samata Manch’ and ‘Milun Saryajani’.

Question 2.
Where are the women’s study centers located in Maharashtra?
Answer:
Women study centers are located at:

• Shrimati Nathibai Damodar Thakersey Women’s University – Mumbai.
• Tata Institute of Social Sciences – Mumbai.
• Savitribai Phule University – Pune
• Shivaji University – Kolhapur.

Question 3.
Do you think International Beauty Pageants can help in creating awareness about women’s issues? why?
Answer:
Yes, International Beauty Pageants can help in creating global awareness on women’s issues world wide.
The participants in these events come from different cultures and backgrounds, they speak on many subjects affecting women which is covered by international media. Concerns pertaining to women’s political rights have been brought to the notice of the world through these pageants.

Answer the following questions in detail:

Question 1.
Explain, in detail, the Anti-liquor movement.
Answer:
(i) In 1992, in Andhra Pradesh, a movement was started against the drinking of alcohol. It received a good response in other States too.

(ii) When the head of the household dies an untimely death due to addiction to alcohol, the family faces a serious crisis which affects women the most.

(iii) Due to alcoholism, they have to deal with extreme sorrow and poverty. This movement got the support of the anti-arrack movement in Andhra Pradesh.

(iv) As a result of a government policy, arrack (a locally produced alcohol) dealers set up shop in every town and village.The poor labouring people began to get addicted to alcohol.

(v) At the same time, a literacy programme was being run in the villages of the State. The Sitama Katha (Sita’s story) was narrated as a part of this programme.

(vi) It was a story about Sita who creates awareness among the people of a village and gets alcohol to be banned from the village.

(vii) In 1992, three youths of Dubuganta village of Nellore district in Andhra Pradesh drowned in a lake, in a state of inebriation, and died.

(viii) At this instance, the women of the village came together and forced the closure of arrack shops.

(ix) The report of this news in the local newspapers had its effect on many other villages.

(x) The movement spread to the entire State and the government had to adopt a strict policy against the sale of alcohol.

Question 2.
Explain the term ‘Nomadic’ and ‘De-notified’ Tribes.
Answer:
(i) Castes and tribes that move from place to place for a livelihood, are included under Nomadic Tribes.
(ii) They live by rearing animals and engaging in some other occupations.
(iii) The British had declared some of them as criminal tribes.
(iv) In the Law of 1871 to curb crimes, some of the main groups were mentioned as criminal tribes and their occupations and movements were banned.
(v) This unjust law was repealed in the post¬independence period.
(vi) And the curbs on these tribes were lifted. They were included under De-notified Tribes.
(vii) Special efforts are made by the government for the purpose of their social and economic development.
(viii) These tribes have been given representation in educational institutions and the government sector.

Question 3.
What do you mean by Scheduled Castes?
Answer:
(i) In the post-independence period, our Constitution adopted the values of freedom, equality, fraternity and social justice.
(ii) In accordance with this, the practice of untouchability was banned by law.
(iii) Untouchability was removed by the 17th paragraph of the Constitution and this class was included in the Scheduled Castes.
(iv) In view of the educational and social backwardness of these castes, they were given reservations in education as well as jobs to facilitate their development.

Question 4.
Write a note on the manifestation of woman power.
Answer:
(i) Women, who have to face the brunt of scarcity of supplies and rising prices, gave a show of their strength as an organised entity in 1972.
(ii) Under the leadership of the socialist leader Mrinal Gore, women in Mumbai participated in a demonstration which came to be known as the laatne morcha (the rolling pin demonstration).
(iii) Commodities like oil, ghee, rava, maida, would become scarce just as Diwali was near at hand. Kerosene would become very expensive.
(iv) Women came together brandishing their rolling pins and took part in the demonstration.
(v) This movement met with success and the public got a glimpse of the united power of women.

Observe the pictures and write relevant information about them:

Question 1.

Answer:
(i) A show of constructive women power was seen during the Chipko Movement in 1973. The trees from the forests in the foothills of Himalayas were to be cut down for commercial purposes.
(ii) The important leaders of the Chipko Movement were: Chandiprasad Bhat, Sunderlal Bahuguna, Gaura Devi, Sudesha Devi and Bachani Devi.

Question 2.

Answer:
(i) In 1992, in Andhra Pradesh a movement was started against the drinking of alcohol.
(ii) In 1992, three youths of Dubuganta village of Nellore district in Andhra Pradesh drowned in lake, in a state of inebriation and died. At this instance, the women of the village came together and forced the closure of arrack shops.
(iii) Arrack is a locally produced alcohol. As a result of a government policy arrack dealers set up shop in every town and village.

Question 3.

Answer:
(i) In 1998, the govt passed the Sati (Prevention) Act with very stringent provisions.
(ii) On 4th Sept. 1987, Roop Kanwar a married woman, committed sati. She did not do this of her own free will, she was coerced into doing so.
The women activists and journalists, Meena Menon, Geeta Seshu, Sujata Anandan, Anu Joseph and Kalpana Sharma investigated the case.

Question 4.

Answer:
(i) The Dowry Prohibition Act of 1961 made both giving and taking of dowry a cognizable criminal offence.
(ii) Even after the enactment of the anti-dowry law investigations still revealed dowry to be the most frequent cause of deaths. This created greater awareness. Thus, Dowry Prohibition (Amendment) Act came into force in 1984.

Std 9 Science Chapter 16 Heredity and Variation Question Answer Maharashtra Board

Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 16 Heredity and Variation Notes, Textbook Exercise Important Questions and Answers.

Class 9 Science Chapter 16 Heredity and Variation Question Answer Maharashtra Board

Class 9 Science Chapter 16 Heredity and Variation Textbook Questions and Answers

1. Complete the following sentences by choosing the appropriate words from the brackets.
(Inheritance, sexual reproduction, asexual reproduction, chromosomes, DNA, RNA, gene)

a. Hereditary characters are transferred from parents to offsprings by …………………………….., hence they are said to be structural and functional units of heredity.
b. Organisms produced by …………………………….. show minor variations.
c. The component which is in the nuclei of cells and carries the hereditary characteristics is called ……………………………..
d. Chromosomes are mainly made up of ……………………………..
e. Organisms produced through …………………………….. show major variations.

2. Explain the following.

a. Explain Mendel’s monohybrid progeny with the help of any one cross.
Answer:

• Mendel brought about a cross between two pea plants with only pair of contrasting characters. This type of cross is called a monohybrid cross.
• Tall pea plants and dwarf pea plants were used in this cross. Hence this is parent generation (P₁).
  
• All the plants produced in F₁ genration are tall, having genotype Tt. This indicates that the gene responsible for tallness in pea plants is dominant over the gene responsible for dwarfness.
• When F₁ plants are self pollinated they produce second filial generation (F₂).
• In F₂ generation both tall and dwarf plants appeared in the ratio 3:1.
• Thus, the genotypic ratio of F₂ generation is 3 (Tall) : 1 (Dwarf) and the genotypic ratio is 1 TT : 2 Tt: 1 tt.

b. Explain Mendel’s dihybrid ratio with the help of any one cross.
Answer:

• In dihybrid cross, Mendel considered two pairs of contrasting characters.
• He made a cross between a pea plant producing rounded and yellow couloured seeds and a pea plant with wrinkled and green coloured seeds.
  
• All the plants produced in F₁ generation had rounded yellow seeds. This is because in pea plants, round shape of seed is dominant over wrinkled shape and yellow colour of seed is dominant over green colour.
• When F₁ plants are self pollinated, they produce four types of gamates – RY, Ry, rY, ry.
• F₂ plants formed by the fusion of four types of male gametes and four types of female gametes, had phenotypes such as round yellow, wrinkled yellow, round green and wrinkled green.
• Also, F₂ generation showed nine different types of genotypes such as RRYY, RRYy, RRyy, RrYY, RrYy, Rryy, rrYY, rrYy, rryy.
• Phenotypic ratio of dihybrid cross is
  
• The genotypic ratio of dihybrid cross is
  

c. Distinguish between monohybrid and dihybrid cross.
Answer:

d. Is it right to avoid living with a person suffering from a genetic disorder?
Answer:

• No, it is not right to avoid living with a person suffering from a genetic disorder.
• Genetic disorders are transmitted from parents to offsprings only and they are non-contagious, i.e., they do not spread from one person to another through contact.

3. Answers the following questions in your own words.

a. What is meant by ‘chromosome’. Explain its types.
Answer:

• The structure in the nucleus of cells that carries the hereditary characteristics is called the chromosome.
• It is made up mainly of nucleic acids and proteins.
• Depending upon the position of the centromere, there are four types of chromosomes.
  

(a) Metacentric: The centromere is exactly at the mid-point in this chromosome, and therefore, it looks like the English letter ‘V’. The arms of this chromosome are equal in length.

(b) Sub-metacentric: The centromere is somewhere near the mid-point in this chromosome which, therefore, looks like the English letter ‘U. One arm is slightly shorter than the other.

(c) Acrocentric: The centromere is near one end of this chromosome which therefore looks like the English letter One arm is much smaller than the other.

(d) Telocentric: The centromere is right at the end of this chromosome making the chromosome look like the English letter ‘i’. This chromosome consists of only one arm.

b. Describe the structure of the DNA molecule.
Answer:

• In 1953, Watson and Crick proposed a model of the DNA molecule.
• As per their model, two parallel threads (strands) of nucleotides are coiled around each other to form a double helix structure. This structure can be compared with a coiled and a flexible ladder.
• Each strand of DNA is made up of many small molecules known as nucleotides.
• Each nucleotide is made up of a molecule of nitrogen base and phosphoric acid joined to a molecule of sugar.
• There are four types of nitrogen bases-adenine, guanine, cytosine and thymine. Adenine and guanine are called as purines while cytosine and thymine are called as pyrimidines.
• Nucleotides are arranged like a chain in the DNA.
• The two threads (strands) of the DNA are comparable to the two rails of the ladder and each rail is made up of alternately joined molecules of sugar and phosphoric acid.
• Each rung of the ladder is a pair of nitrogenous bases joined by hydrogen bonds. Adenine always pairs with thymine and cytosine always pairs with guanine.

c. Express your opinion about the use of DNA fingerprinting.
Answer:

• DNA fingerprinting is the technique in which the sequence of the genes in the DNA of a person, i.e., the genome of the person is identified.
• This technique is useful to identify the lineage and to identify criminals because it is unique to every person.
• It is also useful to identify paternity and maternity disputes etc.
• This technique was developed by Professor of genetics Sir Alec Jeffreys.
• A common method of collecting a reference sample, is in the use of a buccal swab. If this is not available, blood or saliva or hair sample may be used.
• Just like your actual fingerprint, your DNA fingerprint is something that you are born with. It is unique to you.
• DNA fingerprint is very useful in forensic science.

d. Explain the structure, function and types of RNA.
Answer:

• Ribonucleic acid (RNA) is an important nucleic acid of the cell.
• RNA is made up of ribose sugar, phosphate molecules and four types of nitrogenous bases adenine, guanine, cytosine and uracil.
• The nucleotide i.e., smallest unit of the chain of the RNA molecule is formed by the combination of a ribose sugar, phosphate molecule and one of the nitrogen bases.
• Large numbers of nucleotides are bonded together to form the macromolecule of RNA.
• RNA performs the function of protein synthesis.
• According to function, there are three types of RNA:
  (a) Ribosomal RNA (rRNA): It is the component of cellular organelle ribosome. Ribosomes perform the function of protein synthesis.(b) Messenger RNA (mRNA): It carries the information for protein synthesis from genes (i.e. DNA segment in the cell nucleus) to ribosomes (in the cytoplasm) which produce the proteins.(c) Transfer RNA (tRNA): It carries the amino acid up to the ribosomes as per the message of the mRNA.

e. Why is it necessary for people to have their blood examined before marriage?
Answer:

• If people have their blood examined before marriage, the partners will know about the possible genetic diseases that their children might inherit. So they may decide not to have children or not to get married.
• Blood tests before marriage are also done to check for any contagious disease in the partners. This will help to protect the partners from contagious diseases like STDs.

4. Write a brief note on each.

a. Down syndrome
Answer:

• Down syndrome is the disorder arising due to chromosomal abnormality.
• This is the first discovered and described the chromosomal disorder in human beings.
• This disorder is characterized by the presence of 47 chromosomes. It is described as the trisomy of the 21st pair.
• Infants with this disorder have one extra chromosome with the 21st pair in every cell of the body. Therefore, they have 47 chromosomes instead of 46.
• Children suffering from Down syndrome are usually mentally retarded and have a short lifespan. Mental retardation is the most prominent characteristic.
• Other symptoms include short height, short wide neck, flat nose, short fingers, scanty hair, single horizontal crease on palm and a life expectancy of about 16-20 years.

b. Monogenic disorders
Answer:

• Disorders occurring due to mutation in any single gene into a defective one are called monogenic disorders.
• Approximately 4000 disorders of this type are now known.
• Due to abnormal genes, their products are either produced in insufficient quantity or not produced at all.
• It causes abnormal metabolism and may lead to death at a tender age.
• Examples of monogenic disorders are Hutchinson’s disease, Tay-Sachs disease, galactosaemia, phenylketonuria, sickle cell anaemia, cyctic fibrosis, albinism, haemophilia, night blindness etc.

c. Sickle cell anaemia: symptoms and treatment.
Answer:

• Sickle-cell anaemia is a hereditary disease caused due to mutation in a single gene. It is a monogenic disorder.
• Normal haemoglobin has glutamic acid as the 6th amino acid in its molecular structure. However, if it is replaced by valine, the shape/structure of the haemoglobin molecule, changes.
• Due to this, the erythrocytes (RBCs) which are normally biconcave become sickle-shaped. This condition is called sickle-cell anaemia. The oxygen-carrying capacity of haemoglobin in such individuals is very low.
• In this condition, clumping and thereby, destruction of erythrocytes occurs most often. As a result, blood vessels are obstructed and the circulatory system, brain, lungs, kidneys, etc. are damaged.
• Symptoms of sickle-cell anaemia are swelling of legs and hands, pain in joints, severe general body aches, frequent cold and cough, constant low-grade fever, exhaustion, pale face, low haemoglobin count.
• A person suffering from sickle-cell anaemia should take a tablet of folic acid daily.

5. How are the items in groups A, B and C inter-releated?

6. Filling the blanks based on the given relationship.
a. 44 + X : Turner syndrome : : 44 + XXY: – ……………………………..
b. 3:1 Monohybrid : : 9:3:3:1 : ……………………………..
c. Women : Turner syndrome : : Men : ……………………………..
Answer:
a. Klinefelter syndrome
b. Dihybrid
c. Klinefelter syndrome

7. Complete the tree diagram below based on types of hereditary disorders.

Answer:

Class 9 Science Chapter 12 Study of Sound Intext Questions and Answers

Question 1.
How do specific traits or characteristics appear in organisms? (Can you tell; Textbook Page No. 180)
Answer:

• Information necessary for synthesis of a particular protein is stored in the DNA.
• The segment of DNA which contains all the information for synthesis of a particular protein is called a gene for that protein.
• To understand how a specific trait is expressed, let us consider plant height as an example.
• We know that there are growth hormones in plants. Increase in the height of plants depends upon the quantity of growth hormones.
• The quantity of growth hormone produced by a plant depends upon the efficiency of the concerned enzyme.
• Efficient enzymes produce a greater quantity of the hormone due to which the height of the plant increases.
• However, if the enzymes are less efficient, a smaller quantity of hormone is produced leading to the stunting of the plant.
• Thus, the expression of traits is controlled by the genes.

Question 2.
Show the monohybrid cross between (RR) and (rr) and write the phenotypic and genotypic ratio of F₂ generation. (Use your brain power; Textbook Page No. 187)
Answer:
Parental Generation (P₁)

Phenotypic ratio : 3 Round : 1 Wrinkled
Genotypic ratio : 1 RR : 2 Rr : 1 rr

Question 3.
Why did the characteristic of the Rounded- Yellow seeds alone appear in the Fj generation but not the characteristic of the wrinkled- green seeds? (Use your brain power; Textbook Page No. 187)
Answer:

• Rounded-Yellow seeds is a dominant characteristic whereas wrinkled-green seeds is a recessive characteristic.
• Therefore only the characteristic of Rounded- Yellow seeds appeared in the F1 generation.

Question 4.
Do all boys and girls of your class look alike? (Think about it; Textbook Page No. 179)
Answer:

• No, all the boys and girls of my class do not look alike.
• There is a lot of variation among them.

Question 5.
Carefully observe your classmate’s earlobes. (Observe; Textbook Page No. 179)
Answer:

• Most of the classmates have free earlobes while very few have attached ear lobes.
• This shows that in humans free earlobes is a dominant characteristic whereas attached earlobe is a recessive characteristic.

Question 6.
Irrespective of all of us being humans, what difference do you notice in our skin colour? (Observe; Textbook Page No. 179)
Answer:

• Irrespective of all of us being humans, there is a lot of variation in our skin colour. Some people are light-skinned while some are dark-skinned.
• The difference in skin colour is due to the gene responsible for the production of the pigment melanin.

Question 7.
All of you are in std. IX. Why then are some students tall and some short? (Observe; Textbook Page No. 179)
Answer:
Our height is decided by gene. People who are tall have genes for tallness whereas people who are short have genes for shortness and hence the variation.

Class 9 Science Chapter 12 Study of Sound Additional Important Questions and Answers

Choose and write the correct option:

Question 1.
The similarities and differences are all the effect of
(a) Heredity
(b) Fertilization
(c) Evolution
(d) Natural selection
Answer:
(a) Heredity

Question 2.
Each chromosome appears midway during cell division.
(a) Circular
(b) Rod-shaped
(c) Dumbbell-shaped
(d) Bottle-shaped
Answer:
(c) dumbbell-shaped

Question 3.
The chromosome in which the centromere is exactly at the mid-point is called chromosome.
(a) sub-metacentric
(b) metacentric
(c) acrocentric
(d) telocentric
Answer:
(b) metacentric

Question 4.
The chromosome in which the centromere is somewhere near the mid-point is called chromosome.
(a) metacentric
(b) acrocentric
(c) sub-metacentric
(d) telocentric
Answer:
(c) sub-metacentric

Question 5.
The chromosome in which the centromere is near one end of the chromosome is called chromosome.
(a) metacentric
(b) acrocentric
(c) sub-metacentric
(d) telocentric
Answer:
(d) telocentric

Question 6.
Sex chromosomes are called
(a) homologous chromosomes
(b) autosomes
(c) allosomes
(d) metacentric chromosomes
Answer:
(c) allosomes

Question 7.
Which of the following is absent in RNA?
(a) Adenine
(b) Uracil
(c) Cytosine
(d) Thymine
Answer:
(d) Thymine

Question 8.
DNA was discovered by
(a) Watson and Crick
(b) Frederick Miescher
(c) Gregor Johann Mendel
(d) Robert Brown
Answer:
(b) Frederick Miescher

Question 9.
The double helix model of DNA was produced by
(a) Watson and Crick
(b) Frederick Miescher
(c) Gregor Johann Mendel
(d) Robert Hooke
Answer:
(a) Watson and Crick

Question 10.
The molecule of RNA which is a component of the ribosome organelle is called a
(a) mRNA
(b) tRNA
(c) rRNA
(d) DNA
Answer:
(c) rRNA

Question 11.
In a monohybrid cross, the phenotypic ratio of F, generation is
(a) 1 tall: 3 dwarf
(b) 2 tall: 2 dwarf
(c) 3 tall: 1 dwarf
(d) 3 tall: 2 dwarf
Answer:
(c) 3 talhl dwarf

Question 12.
arises due to either inheritance of only X chromosome from parents or due to inactivation of the gender-related part of X-chromosomes.
(a) Down syndrome
(b) Turner syndrome
(c) Klinefelter syndrome
(d) Albinism
Answer:
(b) Turner syndrome

Question 13.
Progenies of normal man and sufferer woman for sickle-cell anaemia will be
(a) all normal
(b) 25% normal and 75% sufferer
(c) all carrier
(d) all sufferer
Answer:
(c) all carrier

Question 14.
is a mitochondrial disorder.
(a) Down syndrome
(b) Cleft palate
(c) Spina bifida
(d) Leber hereditary optic neuropathy
Answer:
(d) Leber hereditary optic neuropathy

Question 15.
is a monogenic disorder.
(a) Haemophilia
(b) Cleft palate
(c) Diabetes
(d) Spina bifida
Answer:
(a) Haemophilia

Question 16.
is a recessive character of pea plant.
(a) Round shape of seeds
(b) White colour of flowers
(c) Green colour of pods
(d) Inflated shape of pods
Answer:
(b) White colour of flowers

Question 17.
is a dominant character of pea plant.
(a) Dwarf height
(b) Yellow colour of pod
(c) Yellow colour of seeds
(d) Terminal position of flower
Answer:
(c) Yellow colour of seeds

Question 18.
is a dominant character in human beings.
(a) Non-rolling tongue
(b) Attached ear lobe
(c) Absence of hair on arms
(d) Free ear lobe
Answer:
(d) Free ear lobe

Question 19.
is a recessive character in human beings.
(a) Absence of hair on arms
(b) Black and curly hair
(c) Free earlobe
(d) Presence of hair on arms
Answer:
(a) Absence of hair on arms

Question 20.
If one parent is normal and one parent is carrier of sickle-cell anaemia, then the progenies will be
(a) all normal
(b) 50% normal and 50% carrier
(c) 50% carrier and 50% sufferer
(d) all carrier
Answer:
(b) 50% normal and 50% carrier

Question 21.
If one parent is carrier and one parent is a sufferer of sickle-cell anaemia, then the progenies will be
(a) 50% normal and 50% carrier
(b) all sufferers
(c) 50% carrier and 50% sufferer
(d) all carrier
Answer:
(c) 50% carrier and 50% sufferer

Find the odd man out:

Question 1.
Adenine, thymine, cytosine, uracil
Answer:
Adenine. It is a purine whereas the others are pyrimidines.

Question 2.
Axillary flower, green pod, green seed, inflated pod
Answer:
Green seed. It is a recessive character of pea plant whereas the others are dominant characters.

Question 3.
Constricted pod, purple flower, axillary flower, yellow seeds.
Answer:
Constricted pod. It is a recessive character of pea plant whereas the others are dominant characters.

Question 4.
Green seeds, wrinkled seeds, terminal flower, green pod.
Answer:
Green pod. It is a dominant character of pea plant whereas the others are recessive characters.

Question 5.
Attached ear lobes, brown and straight hair, non-rolling tongue, presence of hair on arms.
Answer:
Presence of hair on arms. It is a dominant characteristic of human beings whereas the others are recessive characters.

Question 6.
Cystic fibrosis, albinism, spina bifida, sicklecell anaemia.
Answer:
Spina bifida. It is a polygenic disorder whereas the others are monogenic disorders.

Question 7.
Fiutchinson’s disease, phenylketonuria, nightblindness, leber hereditary optic neuropathy.
Answer:
Leber hereditary optic neuropathy. It is a mitochondrial disorder whereas the others are monogenic disorders.

Complete the analogy:

a. Tall plant: Phenotype :: Tt:
b. Dominant trait : Axial position of flower :: Recessive trait:
c. Women : 44 + XX :: Men :
d. Adenine and Guanine : Purine :: Cytosine and Thymine :
Answer:
a. Genotype
b. Terminal position of flower
c. 44 + XY
d. Pyrimidine

Match the columns

Question 1.

Answer:
(1 – c – iv),
(2 – d – v),
(3 – e – i),
(4-b- Hi),
(5 – a – ii)

Question 2.

Answer:
(1 – c),
(2 – d),
(3 – b),
(4 – a)

Question 3.

Answer:
(1 – d),
(2 – a),
(3 – b),
(4 – c)

State whether the following statements are true or false. Correct the false statement:

Question 1.
Offsprings produced through asexual reproduction show greater variations as compared to those produced through sexual reproduction.
Answer:
False. Offsprings produced through asexual reproduction show minor variations as compared to those produced through sexual reproduction.

Question 2.
Information necessary for protein synthesis is stored in the RNA.
Answer:
False. Information necessary for protein synthesis is stored in the DNA.

Question 3.
The quantity of growth hormone produced by a plant depends upon the efficiency of the concerned enzyme.
Answer:
True

Question 4.
The chromosome in which the centromere is exactly at the mid-point is called telocentric chromosome.
Answer:
False. The chromosome in which the centromere is exactly at the mid-point is called metacentric chromosome.

Question 5.
RNA molecules are called master molecules.
Answer:
False. DNA molecules are called master molecules.

Question 6.
The pair of sex chromosomes are called autosomes.
Answer:
False. The pair of sex chromosomes is called allosomes.

Question 7.
In DNA, Adenine always pairs with thymine and cytosine always pairs with guanine.
Answer:
True

Question 8.
In humans there are 23 pairs of autosomes and one pair of allosomes.
Answer:
False. In humans, there are 22 pairs of autosomes and one pair of allosomes.

Question 9.
The phenotypic and genotypic ratios are not same.
Answer:
True

Question 10.
Phenotype means the pairs of genes responsible for the visible characteristics of organisms.
Answer:
False. Phentotype means external appearance of visible characteristics of organisms.

Question 11.
During gamete formation, in Pj generation the pair of gametes separate independently.
Answer:
True

Question 12.
Down syndrome is caused due to monosomy of X chromosome.
Answer:
False. Down syndrome is caused due to trisomy of 21st chromosome.

Question 13.
In Klinefelter syndrome, women are sterile.
Answer:
False. In Klinefelter syndrome, men are sterile as this disorder arises in men due to abnormality in sex chromosome.

Question 14.
If the father and mother are both sufferers or carriers of sickle-cell anaemia, their offsprings are likely to suffer from this disease.
Answer:
True

Question 15.
During fertilization, mitochondria is contributed by the sperm cell and egg cell(ovum).
Answer:
False. During fertilization, mitochondria is contributed by the egg cell (ovum) alone.

Question 16.
Polygenic disorders strictly follow Mendel’s principles of heredity.
Answer:
False. Polygenic disorders do not strictly follow Mendel’s principles of heredity.

Question 17.
Genetic material is transferred in equal quantity from parents to progeny.
Answer:
True

Give scientific reasons:

Question 1.
DNA molecules are called as ‘Master molecules’.
Answer:

• Molecules of DNA are present in all organisms from viruses and bacteria to human beings.
• These molecules control the functioning, growth and division (reproduction) of the cell.
• Genes present in the DNA are also responsible for transfer of hereditary characteristics from parents to offsprings.
• Therefore, DNA molecules are called as ‘Master molecules’.

Question 2.
Phenotypic and genotypic ratios are different.
Answer:

• Phenotype means external appearance or visible characteristics of organisms whereas the genotype is the pairs of genes responsible for the visible characteristics.
• The genes responsible for any particular character are present in pairs.
• Though, there are two genes, the phenotype
  depends on the presence of the dominant gene, e.g. Genotype for tall height of the plant is TT or Tt.
• Therefore, phenotypic and genotypic ratios are different.

Question 3.
A carrier or sufferer of sickle-cell anaemia should avoid marriage with another carrier or sufferer.
Answer:

• Sickle-cell anaemia is a hereditary disease caused due to mutation of a single gene.
• It is a monogenic disorder that occurs due to changes in a gene during conception.
• If father and mother both are sufferers or carriers of sickle-cell anaemia, their offsprings are likely to suffer from the disease.
• Therefore, a carrier or sufferer of sickle-cell anaemia should avoid marriage with another carrier or sufferer.

Question 3.
Mitochondrial disorders are inherited from the mother only.
Answer:

• Mitochondrial DNA becomes defective due to mutation.
• During fertilization, mitochondria are contributed by the egg cell (ovum) alone.
• Hence, mitochondrial disorders are inherited from the mother only.

Question 4.
Tobacco smoking causes cancer.
Answer:

• Tobacco smoke contains harmful chemicals like pyridine, ammonia, aldehyde furfural, carbon monoxide, nicotine, sulphur dioxide etc.
• They cause uncontrolled cell division.
• Tobacco smoke is full of minute carbon particles which cause normal tissue lining of the lung to transform into thickened black tissue. This leads to cancer.
• Therefore, tobacco smoking causes cancer.

Define the following terms:

Question 1.
Gene
Answer:
The segment of DNA which contains all the information for synthesis of a particular protein is called a ‘gene’.

Question 2.
Chromosome
Answer:
The structure in the nucleus of the cells that carries the hereditary characteristics is called chromosome.

Question 3.
Genetics
Answer:
The branch of biology which studies the transfer of characteristics of organism from one generation to the next and genes in particular, is called genetics.

Question 4.
Heredity
Answer:
Transfer of characteristics from parents to offsprings is called heredity.

Question 5.
Homologous chromosomes
Answer:
If the pair consists of chromosomes are similar in shape and organization, they are called homologous chromosomes.

Question 6.
Heterologous chromosomes
Answer:
If the pair which consists of chromosomes are not similar in shape and organization, they are called heterologous chromosomes.

Question 7.
Genetic disorders
Answer:
Diseases or disorders occuring due to abnormalities in chromosomes and mutations in genes are called genetic disorders.

Distinguish between:

Question 1.
DNA and RNA
Answer:

Question 2.
Turner syndrome and Klinefelter syndrome.
Answer:

Write short notes on:

Question 1.
Albinism
Answer:

• Albinism is a monogenic disorder.
• Our eyes, skin and hair have colour due to the brown pigment melanin. In this disease, the body cannot produce melanin.
• The skin becomes pale, hair are white and eyes are usually pink due to absence of melanin pigment in the retina and sclera.

Question 2.
Polygenic disorders.
Answer:

• Polygenic disorders are caused due to mutations in more than one gene.
• In most such cases, their severity increases due to effects of environmental factors on the foetus.’
• Common examples of such disorders are cleft lip, cleft palate, constricted stomach, spina bifida (a defect of the spinal cord), etc. Besides diabetes, blood pressure, heart disorders, asthma and obesity are also polygenic disorders.
• Polygenic disorders do not strictly follow Mendel’s principles of heredity.
• These disorders arise from a complex interaction between environment, life style and defects in several genes.

Question 3.
Turner syndrome.
Answer:

• Turner syndrome is a disorder arising in women due to abnormality in sex chromosomes.
• Turner syndrome arises due to either inheritance of only one X chromosome from parents or due to inactivation of the gender- related part of X-chromosomes.
• Instead of the normal 44 + XX condition, women suffering from Turner syndrome show a 44 + X condition.
• Such women are sterile i.e. unable to have children due to improper growth of the reproductive organ.

Answer the following questions:

Question 1.
What are the main objectives of National Health Mission?
Answer:
The main objectives of National Health Mission are:

• Strengthening of the rural and urban health facilities.
• Controlling various diseases and illnesses.
• Increasing public awareness about health.
• Offering financial assistance to patients through various schemes.

Question 2.
Which were the seven pairs of contrasting characteristics studied by Mendel in pea plant?
Answer:
The seven pairs of contrasting characters studied by Mendel in pea plant were as follows:

Question 3.
Name some dominant and recessive characteristics seen in human beings.
Answer:
Some dominant and recessive characteristics of human beings.

Question 4.
What is Klinefelter syndrome?
Answer:

• Klinefelter syndrome is a disorder arising in men due to abnormalities in sex chromosomes.
• In this disorder, men have one extra X chromosome, hence their chromosomal condition becomes 44 + XXY.
• Such men are usually sterile because their reproductive organs are not well developed.

Question 5.
How is the diagnosis for sickle-cell anaemia made?
Answer:

• Under the National Health Mission scheme, the ‘Solubility Test’ for diagnosis of sickle-cell anaemia is available at all district hospitals.
• Similarly, the confirmatory diagnostic test – ‘Electrophoresis’ is performed at rural and subdistrict hospitals.

Question 6.
Find out the Phenotypic ratio of the following:
(a) Round-Yellow
(b) Wrinkled-Yellow
(c) Round-Green
(d) Wrinkled-Green
Answer:
(a) Round-Yellow: 9
(b) Wrinkled-Yellow: 3
(c) Round-Green: 3
(d) Wrinkled-Green: 1
Phenotypic ratio: 9:3:3:1

Question 7.
Find out the Genotypic ratio of the following:
(a) RRYY
(b) RRYy
(c) RRyy
(d) RrYY
(e) RrYy
(f) Rryy
(g) rrYY
(h) rrYy
(i) rryy
Answer:
(a) RRYY -1
(b) RRYy-2
(c) RRyy-1
(d) RrYY-2
(e) RrYy-4
(f) Rryy-2
(g) rrYY – 1
(h) rrYy – 2
(i) rryy – 1
Genotypic ratio: 1:2:1:2:4:2:1:2:1

Draw neat and labelled diagrams of the following:

Question 1.
Structure of chromosome
Answer:

Question 2.
Types of RNA
Answer:

Answer the following questions:

Question 1.
What are the effects of tobacco consumption?
Answer:

• Smoking of cigarettes and bidis adversely affects the process of digestion.
• It causes a burning sensation in the throat and cough.
• Excessive smoking causes instability and trembling of fingers.
• It causes dry cough which leads to sleeplessness.
• Tobacco consumption can lead to shortening of life span, chronic bronchitis, pericarditis, cancer of the lungs, mouth, larynx (voice box), pharynx, urinary bladder, lips or tongue.
• The nicotine present in tobacco affects the central and peripheral nervous system. Arteries become hard i.e. it causes arteriosclerosis and hypertension.

Question 2.
Complete the table for number of chromosomes in different organisms.
Answer:

Balbharati Maharashtra State Board 9th Std Science Textbook Solutions 

• Information Communication Technology (ICT) Class 9 Science Textbook Solutions
• Reflection of Light Class 9 Science Textbook Solutions
• Study of Sound Class 9 Science Textbook Solutions
• Carbon: An Important Element Class 9 Science Textbook Solutions
• Substances in Common Use Class 9 Science Textbook Solutions
• Life Processes in Living Organisms Class 9 Science Textbook Solutions
• Heredity and Variation Class 9 Science Textbook Solutions
• Introduction to Biotechnology Class 9 Science Textbook Solutions
• Observing Space: Telescopes Class 9 Science Textbook Solutions

Std 9 Science Chapter 7 Energy Flow in an Ecosystem Question Answer Maharashtra Board

Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 7 Energy Flow in an Ecosystem Notes, Textbook Exercise Important Questions and Answers.

Class 9 Science Chapter 7 Energy Flow in an Ecosystem Question Answer Maharashtra Board

Class 9 Science Chapter 7 Energy Flow in an Ecosystem Textbook Questions and Answers

1. Complete the following table (Carefully study the carbon, oxygen and nitrogen cycles).

2. Correct and rewrite the following statements and justify your corrections.
a. Carnivores occupy the second trophic level in the food chain.
b. The flow of nutrients in an ecosystem is considered to be a ‘one-way’ transport.
c. Plants in an ecosystem are called primary consumers.

3. Give reasons.
a. Energy flow through an ecosystem is ‘one way’.
Answer:

• The Sun is the most important source of energy in any ecosystem.
• Green plants of the ecosystem store some amount of solar energy in the form of food.
• Before reaching the decomposers, this energy is passed on from one trophic level to the next.
• Decomposers dissipate some amount of energy in the form of heat.
• However, no part of the energy ever returns to the Sun. Hence, energy flow through an ecosystem is ‘one way’.

b. Equilibrium is necessary in the various bio-geo-chemical cycles.
Answer:

• The cyclic flow of nutrients within an ecosystem is called bio-geo-chemical cycles.
• Nutrients, necessary for the growth of organisms are continuously transferred from abiotic to biotic factors and biotic to abiotic factors within an ecosystem.
• Any imbalance in the cycles will break the link between the biotic and abiotic factors.
• Therefore, equilibrium is necessary between bio-geo-chemical cycles.

c. Flow of nutrients through an ecosystem is cyclic.
Answer:

• All organisms need nutrients for their growth.
• The nutrients carbon, oxygen, nitrogen, iron, calcium etc. are circulated and recycled from the biosphere to living organisms and after their death back to the biosphere.
• Nutrients are taken up by plants and then passed on to the consumers.
• Eventually, after their death, all types of consumers, are decomposed by decomposers like bacteria and fungi and the nutrients are again released into the biosphere and are, used again by living organisms.

Therefore, the flow of nutrients through an ecosystem is cyclic.

4. Explain the following cycles in your own words with suitable diagrams.
a. Carbon cycle.

Answer:

• The circulation and recycling of carbon from the atmosphere to living organisms and after their death back to the atmosphere is called the carbon cycle.
• Abiotic carbon atoms are circulated and recycled into biotic form mainly through photosynthesis and respiration.
• Hence, the carbon cycle is one of the important bio-geochemical cycles.
• Plants convert carbon dioxide into carbohydrates by the process of photosynthesis.
• Similarly, they produce carbon compounds like proteins and fats, too.
• Carnivores feed upon herbivores. In this way, biotic carbon is transported from plants to herbivores, from herbivores to carnivores and from carnivores to apex consumers.
• Main processes in the carbon cycle
  
• Eventually, after death, all types of consumers, are decomposed by decomposers like bacteria and fungi and carbon dioxide is released again into the atmosphere and is used again by living organisms.
• In this way, carbon is continuously passed on from one living organism to another. After the death of living organisms, carbon goes to the atmosphere and is again taken up by living organisms.

b. Nitrogen cycle.
Answer:

• Nitrogen forms 78% i.e. the maximum portion of the atmosphere. It is necessary for the maintenance of the cycle of nature.
• The circulation and recycling of nitrogen gas into the form of different compounds through various biotic and abiotic processes in nature is called the nitrogen cycle.
• All organisms participate in the nitrogen cycle. It is an important component of proteins and nucleic acids.
• As compared to other elements, it is inactive and does not easily combine with other elements. Most organisms cannot use the free form of nitrogen.
• Important processes of nitrogen cycle:
  (a) Nitrogen fixation: Conversion of nitrogen into nitrates and nitrites through atmosphere, industrial and biological processes.
  (b) Ammonification: Release of ammonia through the decomposition of dead bodies and excretory wastes of organisms.
  (c) Nitrification: Conversion of ammonia into a nitrite and then nitrate.
  (d) Denitrification: Conversion of nitrogen compounds into gaseous nitrogen.

c. Oxygen cycle.
Answer:

1. Oxygen forms 21% of the atmosphere. It is also present in the hydrosphere and lithosphere. The circulation and recycling of oxygen within the biosphere is called the oxygen cycle.
2. This cycle, includes both the biotic and abiotic components. Oxygen is continuously produced as well as used up in the atmosphere.
3. Oxygen is highly reactive and it readily reacts with other elements and compounds.
4. As oxygen is found in various forms like molecular oxygen (Oz), water (H,0), carbon dioxide (C02), inorganic compounds etc, the oxygen cycle of the biosphere is extremely complex.
5. Oxygen is released in the process of photosynthesis, whereas it is used up in processes like respiration, combustion, decomposition, corrosion, rusting, etc.

5. What would you do to help maintain the equilibrium in the various bio-geochemical cycles? Explain in brief.
Answer:

• Bio-geo-chemical cycles always involve the achievement of equilibrium, i.e., a balance in the cycling of the nutrients between the spheres.
• Human activities that are known to be environmentally unfriendly can disrupt this balance.
• We should avoid deforestation as trees play an important role in maintaining the balance.
• We should avoid overuse of fertilizers. The fertilizers get washed away in the nearby water bodies disrupting the balance.
• Avoid burning of fossil fuels as these fuels release a large amount of carbon in the form of carbondioxide, thus disrupting the balance.
• Vehicular emissions is another contributor to the disruption in balance of the various cycles.
• These emissions release oxides of nitrogen and carbon and other hazardous air pollutants.
• So, we must use better quality fuel like CNG or ethanol to reduce vehicular emissions.

6. Explain in detail the inter-relationship between the food chain and food web.
Answer:

• Interaction go on continuously between producers, consumers and decomposers.
• There is a definite sequence in these interactions which is called the food chain.
• Each chain consists of four, five or more links.
• An ecosystem consists of many food chains that are interconnected at various levels. Thus, a food web is formed.
• An organism may be the prey for many other organisms.
• For example, an insect feeds upon leaves of various plants but the same insect is the prey for different animals like frog, wall lizard, birds, etc.
• Thus, many food chains interconnected together form an intricate web called as food web.

7. State the different types of bio-geochemical cycles and explain the importance of those cycles.
Answer:

• The different types of bio-geo-chemical cycles are nitrogen, oxygen, carbon, water vapour, iron, calcium, phosphorus, etc.
• Nutrients, necessary for the growth of the organisms are continuously transferred from abiotic to biotic factors and biotic to abiotic factors within an ecosystem.
• These cycles operate continuously through the medium of the biosphere formed by the lithosphere, atmosphere and hydrosphere.
• (iv) The recycling of biological, geological and chemical sources of nutrients takes place through these cycles.
• Nutrients from the biosphere enter the bodies of plants and animals. Eventually, after death, all types of consumers are decomposed by decomposers like bacteria and fungi and they are again released into the biosphere and are used again by living organisms.
• Therefore, these cycles help in maintaining the flow of nutrients and energy through ecosystem and maintaining the equilibrium in the ecosystem.

8. Explain the following with suitable examples.
a. What type of changes occur in the amount of energy during its transfer from plants to apex consumers?
Answer:

• Plants of the ecosystem store some of the solar energy in the form of food.
• Before reaching the decomposers, this energy is passed on from one trophic level to the next.
• At every trophic level, some amount of energy is used by the organism for its own life processes and some amount of energy is lost to the surroundings.
• Decomposers dissipate some amount of energy in the form of heat.
• However, no part of the energy ever returns to the Sun. Hence, such passage of energy is referred to as ‘one way’ transport.
• Therefore, energy is maximum at the base of the pyramid and is least at the apex, e.g.
• phytoplanktons which form the base of the pyramid have 10,000 kcal of energy while humans at the apex have 10 kcal of energy.

b. What are the differences between flow of matter and of energy in an ecosystem? Why?
Answer:

Class 9 Science Chapter 7 Energy Flow in an Ecosystem Intext Questions and Answers

Can you recall?

7 Energy Flow In An Ecosystem Exercises  Question 1.
What is meant by nitrogen fixation?
Answer:
The process of conversion of Nitrogen into nitrates and nitrites is called Nitrogen fixation.

Energy Flow In An Ecosystem Class 9 Questions And Answers Question 2.
Which microbes bring about the process of nitrogen fixation?
Answer:
Rhizobium present in the root nodules of the leguminous plant bring about the process of nitrogen fixation.

Class 9 Science Chapter 7 Energy Flow In An Ecosystem Question 3.
What is meant by ‘ecosystem’?
Answer:
An ecosystem includes all of the living things like plants, animals and other organisms in a given area, interacting with each other and also with non-living environmental factors like weather, earth, sun, soil, climate and atmosphere.

Energy Flow In An Ecosystem Class 9 Exercise 1Question 4.
Which are different types of ecosystems?
Answer:

Class 9 Science Chapter 7 Energy Flow In An Ecosystem Exercise Question 5.
How do interactions take place between biotic and abiotic factors of an ecosystem?
Answer:

• Abiotic factors include non-living factors such as soil, water etc. and biotic factors include all living organisms.
• Both these abiotic and biotic ecosystems are connected through various bio-geo-chemical cycles.
• These connections/interactions are important for the flow of matter and flow of energy.

Class 9 Science Chapter 7 Energy Flow in an Ecosystem Additional Important Questions and Answers

Choose and write the correct option:

Question 1.
An intricate network of food chains is called
(a) Biosphere
(b) Food web
(c) Energy pyramid
(d) Ecosystem
Answer:
(b) food web

Question 2.
Fungi and other microbes are called
(a) Producers
(b) Consumers
(c) Decomposers
(d) Omnivores
Answer:
(c) decomposers

Question 3.
Oxygen forms of the atmosphere.
(a) 78%
(b) 21%
(c) 10%
(d) 90%
Answer:
(b) 21%

Question 4.
Microbes which do not need oxygen are called
(a) Producers
(b) Aerobes
(c) Anaerobes
(d) Decomposers
Answer:
(c) anaerobes

Question 5.
The pattern of energy exchange in an ecosystem is called a
(a) Food chain
(b) Food web
(c) Pyramid of energy
(d) Trophic levels
Answer:
(c) Pyramid of energy

Question 6.
Carbon atoms are circulated and recycled through
(a) Nitrification and denitrification
(b) Photosynthesis and respiration
(c) Respiration and nitrification
(d) Photosynthesis and ammonification
Answer:
(b) photosynthesis and respiration

Question 7.
Conversion of ammonia into a nitrite and then nitrate is called
(a) Nitrogen fixation
(b) Denitrification
(c) Nitrification
(d) Ammonification
Answer:
(c) nitrification

Question 8.
The conversion of nitrogen compounds into gaseous nitrogen is called
(a) Nitrogen fixation
(b) Denitrification
(c) Ammonification
(d) Nitrification
Answer:
(b) denitrification

Question 9.
is an important component of proteins and nucleic acids.
(a) Carbon
(b) Nitrogen
(c) Phosphorus
(d) Oxygen
Answer:
(b) Nitrogen

Question 10.
Amount of matter and energy from the lowest level to the highest level.
(a) decreases
(b) increases
(c) remains the same
(d) multiplies
Answer:
(a) decreases

Question 11.
is the most important source of energy in any ecosystem.
(a) The Sun
(b) The Moon
(c) Producers
(d) Decomposers
Answer:
(a) The Sun

Question 12.
Flow of energy in an ecosystem is
(a) cyclical
(b) two way transport
(c) o ne way transport
(d) to and fro transport
Answer:
(c) one way transport

Question 13.
The Indian Institute of Ecology and Environment, Delhi, has published
(a) Invasive species in a changing Environment
(b) Encyclopaedia of Ecology and Environment
(c) Environment and Ecology Magazine
(d) Biodiversity and Disaster Management
Answer:
(b) Encyclopaedia of Ecology and Environment

Question 14.
Oxygen is released in the process of
(a) Respiration
(b) Decomposition
(c) Combustion
(d) Photosynthesis
Answer:
(d) photosynthesis

Question 15.
cycle is a gaseous cycle.
(a) Carbon
(b) Phosphorus
(c) Calcium
(d) Iron
Answer:
(a) Carbon

Question 16.
is a sedimentary cycle.
(a) Carbon
(b) Nitrogen
(c) Oxygen
(d) Calcium
Answer:
(d) Calcium

Question 17.
is a primary consumer.
(a) Elephant
(b) Frog
(c) Owl
(d) Tiger
Answer:
(a) Elephant

Question 18.
is a secondary consumer.
(a) Grasshopper
(b) Elephant
(c) Frog
(d) Human
Answer:
(c) Frog

Question 19.
Tiger is a /an
(a) Producer
(b) Primary consumer
(c) Apex consumer
(d) Secondary consumer
Answer:
(c) apex consumer

Question 20.
Carbon dioxide is released into the atmosphere through
(a) burning of fossil fuels
(b) volcanic activity
(c) respiration
(d) all of these
Answer:
(d) all of these

Question 21.
in 1942 studied the food chain and energy flow through it
(a) Linderman
(b) Darwin
(c) Calypso
(d) Chu win lee
Answer:
(a) Linderman

Question 22.
fter the death of apex consumers, energy becomes available to.
(a) Decomposers
(b) Producers
(c) Herbivores
(d) Carnivores
Answer:
(a) Decomposers

Question 23.
Green plants of the ecosystem store in the form of food.
(a) Solar energy
(b) Chemical energy
(c) Thermal energy
(d) Electrical energy
Answer:
(a) Solar energy

Question 24.
Plants convert carbon dioxide into by the process of photosynthesis.
(a) Carbohydrates
(b) Proteins
(c) Fats
(d) Vitamins
Answer:
(a) Carbohydrates

Question 25.
Carnivores feed upon
(a) Decomposers
(b) Herbivores
(c) Producers
(d) Secondary producers
Answer:
(b) Herbivores

Question 26.
is used up in the processes like respiration, combustion, decomposition, corrosion, rusting, etc.
(a) Nitrogen
(b) Oxygen
(c) Argon
(d) Helium
Answer:
(b) Oxygen

Question 27.
Nitrogen forms % of the atmosphere.
(a) 79
(b) 78
(c) 21
(d) 2
Answer:
(b) 78

Question 28.
Most organisms cannot use the free form of
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Carbon monoxide
Answer:
(b) Nitrogen

Question 29.
first proposed the concept of Ecological Pyramid in 1927.
(a) Darwin
(b) Newton
(c) Elton
(d) Edison
Answer:
(c) Elton

Question 30.
Ecological Pyramid is called
(a) Hills
(b) Mounts
(c) Eltonian
(d) Darwinism
Answer:
(c) Eltonian

Question 31.
is produced from oxygen through various atmospheric processes.
(a) Nitrogen dioxide
(b) Nitrites
(c) Ozone
(d) CFC
Answer:
(c) Ozone

Question 32.
Interactions between producers, consumers and saprophytes in a definite sequence is called
(a) Links
(b) Internet
(c) Food chain
(d) Connectors
Answer:
(c) Food chain

Question 33.
Many food chains interconnected at various levels is called
(a) Links
(b) Internet
(c) Connectors
(d) Food web
Answer:
(d) Food web

Question 34.
Decomposers dissipate some amount of energy in the form of
(a) Light
(b) Electricity
(c) Sound
(d) Heat
Answer:
(d) Heat

Question 35.
The flow of nutrients in an ecosystem is
(a) Non- cyclic
(b) Mono directional
(c) Reverse directional
(d) Cyclical
Answer:
(d) Cyclical

Question 36.
The cyclical flow of nutrients within an ecosystem is called
(a) Biological cycle
(b) Chemical cycle
(c) Solar cycle
(d) Bio-geo chemical cycle
Answer:
(d) Bio-geo chemical cycle

Question 37.
is an accumulation of the main abiotic gaseous nutrient materials found in the earth’s atmosphere.
(a) Gaseous cycle
(b) Water cycle
(c) Solar cycle
(d) Lunar cycle
Answer:
(a) Gaseous cycle

Question 38.
Oxygen is released into the atmosphere by the process of
(a) Photosynthesis
(b) Respiration
(c) Oxidation
(d) Decomposition
Answer:
(a) Photosynthesis

Question 39.
Charles Elton studied the of the Beer islands in England..
(a) Tundra ecosystem
(b) Mediterranean ecosystem
(c) Equatorial ecosystem
(d) Taiga ecosystem
Answer:
(a) Tundra ecosystem

Question 40.
in 1942 studied the food chain and energy flow through it.
(a) Charles Elton
(b) Lindeman
(c) Robert Whittaker
(d) Eichler
Answer:
(b) Lindeman

Question 41.
After the death of apex consumers, energy becomes available to
(a) Primary consumer
(b) Secondary consumer
(c) Decomposer
(d) Sun
Answer:
(c) Decomposer

Question 42.
Nitrogen forms % of the atmosphere.
(a) 28%
(b) 78%
(c) 48%
(d) 82%
Answer:
(b) 78%

Question 43.
first proposed the concept of the Ecological Pyramid in 1927.
(a) Charles Elton
(b) Lindeman
(c) Eichler
(d) John Muir
Answer:
(a) Charles Elton

Question 44.
Oxygen is released into the atmosphere by the process of
(a) respiration
(b) Photosynthesis
(c) Combustion
(d) All of these
Answer:
(b) Photosynthesis

Find the odd man out:

Question 1.
Photosynthesis, Respiration, Decomposition, Forest Fires
Answer:
Forest Fires

Question 2.
Combustion, Corrosion, rusting, formation of ozone, Photosynthesis
Answer:
Photosynthesis

Question 3.
Biological nitrogen fixation, ammonification, nitrification, denitrification, industrial nitrogen fixation
Answer:
Industrial nitrogen fixation

Question 4.
Frog, Owl, Squirrel, Fox
Answer:
Squirrel

Question 5.
Grasshopper, squirrel, elephant, lion
Answer:
Lion

Question 6.
Nitrogen cycle, oxygen cycle, carbon cycle, phosphorus cycle
Answer:
Phosphorus cycle

Question 7.
Photosynthesis, Nitrification, Ammonification, Denitrification
Answer:
Photosynthesis

Find out the correlation:

1. Grasshopper : Primary consumer :: Tiger : ………………..
2. Owl : Secondary consumer :: Squirrel : ………………..
3. Flow of energy : One way :: Flow of nutrients : ………………..
4. Plants : Producers :: Bacteria and Fungi : ………………..
5. Nitrogen : Gaseous cycle :: Phosphorus : ………………..
6. Oxygen : 21% :: Nitrogen : ………………..
7. Photosynthesis: Carbon cycle:: Ammonification : ………………..
8. Respiration : Oxygen cycle :: Nitrification : ………………..
9. Respiration : Biotic process :: Combustion : ………………..
10. Microbes using oxygen : Aerobes :: Microbes not using oxygen : ………………..
Answer:
(1) Apex consumer
(2) Primary consumer
(3) Cyclic
(4) Decomposers
(5) Sedimentary cycle
(6) 78%
(7) Nitrogen cycle
(8) Nitrogen cycle
(9) Abioticprocess
(10) Anaerobes

Q.l. (B) 3. Difference between:
(1) Azotobacter and Rhizobium
Answer:

(2) Biotic components and Abiotic component
Answer:

(3) Producers and Herbivores
Answer:

(4) Carnivores and Herbivores
Answer:

(5) Phosphorus and Carbon
Answer:

(6) Food chain and Food web
Answer:

State whether the following statements are true or false. Correct the false statements:

(1) Herbivores occupy the third trophic level in a food chain.
(2) Apex consumers use herbivores and carnivores as their food.
(3) Humans are apex consumers.
(4) Omnivores feed only on carnivores.
(5) A food chain has two links.
(6) The number of consumers in a food web is fixed.
(7) The amount of matter and energy goes on increasing at every level in a food chain.
(8) Robert Brown first proposed the concept of Ecological Pyramid.
(9) After the death of apex consumers, the energy becomes available to decomposers.
(10) The gaseous cycle is a speedier cycle than the sedimentary cycle.
(11) Climatic changes and human activities seriously affect the speed, intensity and equilibrium of bio-geo-chemical cycles.
(12) Carbon dioxide is released in the atmosphere through photosynthesis.
(13) The equilibrium of oxygen and carbon dioxide gases is maintained by decomposers.
(14) The conversion of ammonia into a nitrite and then nitrate is called nitrogen fixation.
(15) Conversion of nitrogen compounds into gaseous nitrogen is called nitrogen fixation.
(16) Release of ammonia through decomposition of dead plants and excretory wastes of organisms is called ammonification.
(17) The cyclic flow of nutrients within an ecosystem is called Energy Pyramid.
Answer:
(1) False, herbivores occupy the second trophic level in a food chain as they are directly dependent on producers.
(2) True
(3) True
(4) False. Omnivores feed on both herbivores and carnivores.
(5) False. A food chain consists of four, five or more links.
(6) False. A food web can have many consumers.
(7) False. The amount of matter and energy goes on decreasing at every level in a food chain.
(8) False. Charles Elton first proposed the concept of Ecological Pyramid.
(9) True
(10) True
(11) True
(12) False. Carbon dioxide is released in the atmosphere through respiration, burning of fossil fuels and wood, forest fires and volcanic activity. (13) False. The equilibrium of oxygen and carbon dioxide gases is maintained by plants.
(14) False. The conversion of ammonia into a nitrite and then nitrate is called nitrification.
(15) False. Conversion of nitrogen compounds into gaseous nitrogen is called denitrification.
(16) True
(17) False. The cyclic flow of nutrients within an ecosystem is called bio-geochemical cycle.

Name the following:

Question 1.
The animals that feed on herbivores.
Answer:
Carnivores.

Question 2.
Organisms that feed on herbivores and carnivores.
Answer:
Omnivores.

Question 3.
Two examples of primary consumers.
Answer:
Grasshopper, squirrel.

Question 4.
Two examples of secondary consumers.
Answer:
Frog, owl.

Question 5.
Two examples of Apex consumers.
Answer:
Lion, tiger.

Question 6.
Levels in the food chain.
Answer:
Trophic level.

Question 7.
Organisms that decompose the dead bodies of plants and animals.
Answer:
Decomposers.

Question 8.
Process which releases oxygen.
Answer:
Photosynthesis.

Question 9.
Release of ammonia through decomposition of dead bodies and excretory wastes of organisms.
Answer:
Ammonification.

Question 10.
Conversion of nitrogen into nitrates and nitrites through atmospheric, industrial and biological processes.
Answer:
Nitrogen fixation.

One line answers:

Question 1.
What is Food chain?
Answer:
Interactions between producers, consumers and decomposers in a definite sequence is called as a food chain.

Question 2.
What is Food web?
Answer:
The interconnection among different food chains in an ecosystem at various levels is called as a food web.

Question 3.
What is Trophic level?
Answer:
A trophic level is the step at which the organism obtains its food in the chain.

Question 4.
What is Pyramid of energy?
Answer:
The pattern of energy exchange in an ecosystem is called a ‘Pyramid of energy’.

Question 5.
What is Bio-geo-chemical cycle?
Answer:
The cyclical flow of nutrients within an ecosystem is called bio-geo-chemical cycle.

Question 6.
What is Carbon cycle?
Answer:
The circulation and recycling of carbon from the atmosphere to living organisms and aher their death back to the atmosphere is called the carbon cycle.

Question 7.
What is Oxygen cycle?
Answer:
The circulation and recycling of oxygen within the biosphere is called as oxygen cycle.

Question 8.
What is Nitrogen cycle?
Answer:
The circulation and recycling of nitrogen gas into the form of different compounds through various biotic and abiotic processes in nature is called the nitrogen cycle.

Question 9.
What is Nitrogen fixation?
Answer:
The process of conversion of free nitrogen gas of the atmosphere into nitrogen compounds is called of nitrogen fixation.

Distinguish between:

Question 1.
Gaseous Cycle and Sedimentary Cycle.
Answer:

Question 2.
Carbon Cycle and Nitrogen Cyde.
Answer:

Complete the flow chart:

Question 1.
Energy Pyramid.

Question 3.
Nitrogen Cycle

Question 4.
Bio-Geo Chemical cycle

Write short notes on:

Question 1.
Trophic level.
Answer:

• Each level in the food chain is called a trophic level.
• A trophic level is the step at which the organism obtains its food in the chain.
• The amount of matter and energy gradually decreases from producers at the lowest level to the top consumers at the highest level.

Question 2.
Food web.
Answer:

• An ecosystem consists of many food chains that are interconnected at various levels. This is called food web.
• An organism may be the prey for many other organisms.
• For example, an insect feeds upon leaves of various plants but the same insect is the prey for different animals like wall lizards, birds etc.
• This forms an intricate web instead of a linear food chain. Such an intricate network is called as food web.
• Generally food webs are formed everywhere in nature.

Question 3.
Energy Pyramid.

Answer:

• Each level in the food chain is called a trophic level.
• The amount of matter and energy gradually decreases from producers at the lowest level to the top consumers at the highest level.
• The initial quantity of energy goes on decreasing at every level of energy exchange.
• Similarly, the number of organisms also decreases from the lowest level to the highest level.
• This pattern of energy exchange in an ecosystem is called a Pyramid of energy.

Explain the following statements

Question 1.
justify the statements
(a) Producers form the first trophic level in the food chain. Herbivores depend directly on producers.
(b) The flow of nutrients in an ecosystem is cyclic.
(c) Plants in an ecosystem are called autotrophs.
Answer:

1. So herbivores form the second trophic level, whereas carnivores depend on herbivores, so they form the third trophic level in the food chain.
2. The nutrients are circulated and recycled from the biosphere to living organisms and after their death back to the biosphere.
3. They produce their own food by the process of photosynthesis. All animals in an ecosystem directly or indirectly depend on plants for food.

Explain the diagram

Question 1.
Food chain in a forest ecosystem:

Answer:

• In a forest ecosystem, grass is eaten by a deer, which in turn is eaten by a tiger.
• The grass, deer and tiger form a food chain.
• In this food chain, energy flows from the grass (producer) to the deer (primary consumer) to the tiger (secondary consumer).

Question 2.
Food chain in an aquatic ecosystem (Pond)

Answer:

• In a aquatic ecosystem algae are eaten by insects.
• Insects are eaten by small fish, small fish are in turn eaten by big fish.
• And the big fish are eaten by fish eating birds.
• In this food chain, energy flows from the algae (producer) to the insects (primary consumers) to the small fish (secondary consumers) to the big fish (tertiary consumer) and to the fish eating birds (apex consumer).

Question 3.
Carbon cycle

Answer:

• The circulation and recycling of carbon from the atmosphere to living organisms and after their death back to the atmosphere is called carbon cycle.
• Main processes involved in carbon cycle are photosynthesis and respiration.
• Carbon in the form of carbon dioxide is directly absorbed by plants for photosynthesis

Question 4.
Nitrogen cycle

Answer:
(i) The circulation and recycling of nitrogen into the form of different compounds through various biotic and abiotic processes in nature is called the nitrogen cycle.
(ii) Main processes involved in nitrogen cycle are nitrogen fixation, ammonification, nitrification and denitrification.
(iii) Nitrogen gas cannot be directly absorbed by plants. So nitrogen is fixed by the process of nitrogen fixation and then absorbed from the soil.

Question 5.
Oxygen cycle

Answer:

1. Oxygen forms 21% of the atmosphere. It is also present in the hydrosphere and lithosphere.
2. Circulation and recycling of oxygen within the biosphere is called the oxygen cycle.
3. This cycle, includes both the biotic and abiotic components.
4. Oxygen is continuously produced as well as used up in the atmosphere.
5. Oxygen is highly reactive and it readily reacts with other elements and compounds.
6. As oxygen is found in various forms like molecular oxygen (O₂), water (H₂O), carbon dioxide (CO₂), inorganic compounds etc, the oxygen cycle of the biosphere is extremely complex.
7. Oxygen is released in the process of photosynthesis, whereas it is used up in processes like respiration, combustion, decomposition, corrosion, rusting, etc.

Answers based on figures.

Question 1.
Nitrogen Cycle

Answer:

• Oxygen forms 21% of the atmosphere. It is also present in the hydrosphere and lithosphere.
• The circulation and recycling of oxygen within the biosphere is called the oxygen cycle.
• This cycle, includes both the biotic and abiotic components.
• Oxygen is continuously produced as well as used up in the atmosphere.
• Oxygen is highly reactive and it readily reacts with other elements and compounds.
• As oxygen is found in various forms like molecular oxygen (O₂), water (H₂O), carbon dioxide (CO₂), inorganic compounds etc, the oxygen cycle of the biosphere is extremely complex.
• Oxygen is released in the process of photosynthesis, whereas it is used up in processes like respiration, combustion, decomposition, corrosion, rusting, etc.

Answers based on figures.

Question 1.
Nitrogen Cycle

(i) Is nitrogen a reactive gas?
Answer:
Nitrogen in its atmospheric state non-reactive gas

(ii) Name process of nitrogen conversion from atmosphere to green plants.
Answer:
Nitrogen fixation is the process of nitrogen conversion atmosphere to green plants

(iii) Name the process of converting usable nitrogenous products into atmospheric inert nitrogen.
Answer:
Denitrification is the process of converting usable nitrogenous products into atmospheric inert nitrogen

(iv) Animals produce which product of nitrogen?
Answer:
Animals produce ammonia as a product of nitrogen

(v) Name two nitrifying organisms.
Answer:
Azotobacter and Rhizobium are the two nitrifying organisms

(vi) Which type of bio-geo-chemical cycles does nitrogen follow?
Answer:
Nitrogen follows gaseous and sedimentary bio-geo-chemical cycles

Question 2.
Carbon cycle

(i) Is carbon dioxide gas freely available in the atmosphere?
Answer:
Carbon dioxide gas is freely available in the atmosphere

(ii) How is carbon found in water?
Answer:
Carbon is found in water in the form of carbonates

(iii) How are we using carbon as a fuel?
Answer:
Fossil fuels are a form of carbon which are used as fuel by us

(iv) How to plants use carbon as their food source?
Answer:
Plants take up carbon in photosynthesis and convert it into starch which is their food source

(v) How do animals use carbon?
Answer:
Animals use carbon in form of organic compounds and inorganic compounds

(vi) Which type of bio-geo-chemical cycles does carbon follow?
Answer:
Carbon follows gaseous and sedimentary bio-geo-chemical cycles

Question 3.
Oxygen cycle

(i) Is oxygen gas freely available in the atmosphere?
Answer:
Oxygen gas is freely available in the atmosphere

(ii) How is oxygen used by animals?
Answer:
Oxygen is used in respiration by the animals

(iii) How are we using carbon as a fuel?
Answer:
Fossil fuels are a form of carbon which are used as fuel by us

(iv) How to plants use carbon as their food source?
Answer:
Plants take up carbon in photosynthesis and convert it into starch which is their food source

(v) How do animals use carbon?
Answer:
Animals use carbon in form of organic compounds and inorganic compounds

(vi) Which type of bio-geo-chemical cycles does carbon follow?
Answer:
Carbon follows gaseous and sedimentary biogeo-chemical cycles

Question 4.
Food web

(i) What is the basic unit of food web?
Answer:
The basic unit of food web is food chain

(ii) Which organisms are on the 1st level of this food web?
Answer:
Producers are p. the 1st level of this food web

(iii) What are the animals which depend on producers directly for nutrition called?
Answer:
The animals which depend on producers directly for nutrition are called Herbivores

(iv) What are the animals which eat any type of food for nutrition called?
Answer:
The animals which eat any type of food for nutrition are called Omnivore

(v) What will happen if one animal in the food chain goes extinct?
Answer:
If one animal in the food chain goes extinct the entire food chain collapse

(vi) What are the factors badly affecting the food web?
Answer:
Factors like hunting, pollution, deforestation, human-animal conflicts etc. are the factors badly affecting the food web

Complete the paragraph

(1) Elemental oxygen is normally found in the form of a diatomic molecule. However, in the upper reaches of the atmosphere, a molecule containing three atoms of oxygen is found. This would mean a formula of 03 and this is called ozone. Unlike the normal diatomic molecule of oxygen, ozone is poisonous and we are lucky that it is not stable nearer to the Earth’s surface. But it performs an essential function where it is found. It absorbs harmful radiations from the Sun. This prevents those harmful radiations from reaching the surface of the Earth where they may damage many forms of life.

Recently it was discovered that this ozone layer was getting depleted. Various man-made compounds like CFCs (carbon compounds having both fluorine and chlorine) which are very stable and not degraded by any biological process) were found to persist in the atmosphere. Once they reached the ozone layer, they would react with the ozone molecules. This resulted in a reduction of the ozone layer and recently they have discovered a hole in the ozone layer above the Antarctica. It is difficult to imagine the consequences for life on Earth if the ozone layer dwindles further, but many people think that it would be better not to take chances. These people advocate working towards stopping all further damage to the ozone layer.

(2) The utilisation of glucose to provide energy to living things involves the process of respiration in which oxygen may or may not be used to convert glucose back into carbon dioxide. This carbon dioxide then goes back into the atmosphere. Another process that adds to the carbon dioxide in the atmosphere is the process of combustion where fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial processes.

In fact, the percentage of carbon dioxide in the atmosphere is said to have doubled since the industrial revolution when human beings started burning fossil fuels on a very large scale. Carbon, like water, is thus cycled repeatedly through different forms by the various physical and biological activities. Heat is trapped by glass, and hence the temperature inside a glass enclosure will be much higher than the surroundings. This phenomenon was used to create an enclosure where tropical plants could be kept warm during the winters in colder climates. Such enclosures are called greenhouses.

Greenhouses have also lent their name to an atmospheric phenomenon. Some gases prevent the escape of heat from the Earth. An increase in the percentage of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect. Carbon dioxide is one of the greenhouse gases. An increase in the carbon dioxide content in the atmosphere would cause more heat to be retained by the atmosphere and lead to global warming.

(3) Nitrogen gas makes up 78% of our atmosphere and nitrogen is also a part of many molecules essential to life like proteins, nucleic acids (DNA and RNA) and some vitamins. Nitrogen is found in other biologically important compounds such as alkaloids and urea too. Nitrogen is thus an essential nutrient for all life-forms and life would be simple if all these life-forms could use the atmospheric nitrogen directly. However, other than a few forms of bacteria, life-forms are not able to convert the comparatively inert nitrogen molecule into forms like nitrates and nitrites which can be taken up and used to make the required molecules.

These nitrogen-fixing bacteria may be free-living or be associated with some species of dicot plants. Most commonly, the nitrogenfixing bacteria are found in the roots of legumes (generally the plants which give us pulses) in special structures called root nodules. Other than these bacteria, the only other manner in which the nitrogen molecule is converted to nitrates and nitrites is by a physical process. During lightning, the high temperatures and pressures created in the air convert nitrogen into oxides of nitrogen. These oxides dissolve in water to give nitric and nitrous acids and fall on land along with rain. These are then utilised by various lifeforms.

Read the paragraph and answer the questions:

(1) Nitrogen cycle
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among the atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification, The majority of Earth’s atmosphere (78%) is atmosphere nitrogen, making it the largest source of nitrogen.

However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition, Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle. Human modification of the global nitrogen cycle can negatively affect the natural environment system and also human health.

(i) Why nitrogen cycle is called bio-geochemical cycle?
Answer:
Nitrogen cycle is called bio-geochemical cycle as it undergoes biological as well as geochemical processes.

(ii) Why is nitrogen cycle important to us?
Answer:
Nitrogen cycle is important to us as nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition.

(iii) Name important process of nitrogen cycle.
Answer:
Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification.

(iv) What can affect the nitrogen cycle negatively?
Answer:
Human modification of the global nitrogen cycle can negatively affect the natural environment system and also human health.

(v) Which human activities change the nitrogen cycle?
Answer:
Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle.

(2) Food web
A food chain is a linear network of links in a food i web starting from producer organisms (such asgrass or trees which use radiation from the Sun to make their food) and ending at apex predator species (like grizzly bears or killer whales), detritivores (like earthworms or woodlice), ordecomposer species (such as fungi or bacteria), A food chain also shows how the organisms are related with each other by the food they eat. Each level of a food chain represents a different trophiclevel. A food chain differs from a food web, because the complex network of different animal’s feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time.

Natural interconnections between food chains make it a food web. A common metric usedto the quantify food web trophic structure is foodi chain length. In its simplest form, the length of a chain is the number of links between a trophici consumer and the base of the web and the meanchain length of an entire web is the arithmetic average of the lengths of all chains in a food web. The food chain is an energy source diagram. Many food webs have a keystone species. A keystonespecies is a species that has a large impact on thei surrounding environment and can directly affectthe food chain.

If this keystone species dies off it can set the entire food chain off balance. Keystonespecies keep herbivores from depleting all of thei foliage in their environment and preventing ai mass extinction. Food chains were first introduced by the Arab scientist and philosopher Al-Jahiz inthe 10th century and later popularized in a book I published in 1927 by Charles Elton, which also i introduced the food web concept.

(i) What is a food web?
Answer:
Food web is a linear network of links of food chains.

(ii) In a food web which organism are called producers?
Answer:
In a food web which organism which can produce food by photosynthesis are called producers.

(iii) What is the role of keystone species?
Answer:
Keystone species keep herbivores from depleting all of the foliage in their environment and preventing a mass extinction.

(iv) What is a keystone species?
Answer:
A keystone species is a species that has a large impact on the surrounding environment and can directly affect the food chain.

(v) What does each level of food chain represent?
Answer:
Each level of a food chain represents a different trophic level.

(3) Carbon cycle
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as long-term processes of carbon sequestration to and release from carbon sinks.

The carbon cycle was discovered by Antoine! Lavoisier and Joseph Priestley, and popularised by Humphry Davy. Carbon in the Earth’satmosphere exists in two main forms carbon dioxide and methane. Both of these gases absorb and retain heat in the atmosphere and are partially responsible for the greenhouse effect. Methane produces a larger greenhouse effect per volume as compared to carbon dioxide, but it exists in much lower concentrations and is more short-lived than carbon dioxide, making carbon dioxide the more important greenhouse gas of the two.

Carbon dioxide is removed from the atmosphere primarily through photosynthesis and enters the terrestrial and oceanic biospheres. Carbon dioxide also dissolves directly from the atmosphere into bodies of water (ocean, lakes, etc.), as well as dissolving in precipitation as raindrops fall through the atmosphere. When dissolved in water, carbon dioxide reacts with water molecules and forms carbonic acid, which contributes to ocean acidity. It can then be absorbed by rocks through weathering. It also can acidify other surfaces it touches or be washed into the ocean.

(i) Which gas has greener house effect as compared to CO₂?
Answer:
Methane gas CH₄ has greener house effect as compared to CO₂.

(ii) How does dissolved CO₂ affect oceans?
Answer:
When dissolved in water, carbon dioxide reacts with water molecules and forms carbonic acid, which contributes to ocean acidity.

(iii) Why is carbon cycle called bio-geochemical cycle?
Answer:
The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth.

(iv) How is carbon dioxide removed from atmosphere?
Answer:
Carbon dioxide is removed from the atmosphere primarily through photosynthesis and enters the terrestrial and oceanic biospheres.

(v) Who discovered the carbon cycle?
Answer:
The carbon cycle was discovered by Antoine Lavoisier and Joseph Priestley.

Answer the questions in detail:

Question 1.
Write the important processes of the nitrogen cycle.
Answer:

• Nitrogen fixation: Conversion of nitrogen into nitrates and nitrites through atmospheric, industrial and biological processes.
• Ammonification: Release of ammonia through decomposition of dead bodies and excretory wastes of organisms.
• Nitrification: Conversion of ammonia into a nitrite and then nitrate.
• Denitrification: Conversion of nitrogen components into gaseous nitrogen.

Make a concept diagram and explain.

Question 1.
Food chain

Answer:
According to the mode of nutrition the organisms are classified into producers, consumers, saprotrophs (saprophytes) and decomposers. Primary consumers are directly dependent on autotrophs (producers), e.g.: Grasshopper, squirrel, elephant) Secondary consumers use herbivores as their food, e.g.: Frog, owl, fox, etc. Apex or top consumers use herbivores and carnivores as their food. No animals feed on top consumers, e.g.: Tiger, lion, etc. Omnivores feed on herbivores and carnivores, e.g.: Humans, bear, etc. A continuous interaction between producers, consumers and decomposers in a definite sequence is called as food chain.

Food chain, in ecology is the sequence of transfers of matter and energy in the form of food from organism to organism. Food chains intertwine locally into a food web because most organisms consume more than one type of animal or plant. Plants, which convert solar energy to food by photosynthesis, are the primary food source. In a predator chain, a plant-eating animal is eaten by a flesh-eating animal. In a parasite chain, a smaller organism consumes part of a larger host and may itself be parasitized by even smaller organisms. In a saprophytic chain, microorganisms live on dead organic matter.

Question 2.
Energy pyramid
Answer:

An energy pyramid is a model that shows the flow of energy from one trophic, or feeding, level to the next in an ecosystem. The model is a diagram that compares the energy used by organisms at each trophic level. The energy in an energy pyramid is measured in units of kilocalories (kcal). Energy pyramids are similar to biomass pyramids, another type of trophic pyramid that models the amount of biomass at each trophic level in an ecosystem, energy flow in ecosystems. The structure of an energy pyramid reflects the trophic structure of an ecosystem.

The pyramid is divided into trophic levels similar to those in a food chain. At the pyramid base are the producers, autotrophic organisms that make their own food from inorganic substances. All of the other organisms in the energy pyramid are consumers. These are heterotrophs, meaning that they get food energy by consuming other organisms. The consumers at each trophic level feed on organisms from the level below and are themselves consumed by organisms at the level above. Primary consumers are organisms that consume producers; thus, most primary consumers are herbivores, though some may be detrivores (organisms that feed on decaying organic matter).

Secondary consumers are carnivores that feed on primary consumers and tertiary consumers are carnivores that eat secondary consumers. In rare instances, an ecosystem may have an additional trophic level composed of quaternary consumers camivores that consume tertiary consumers’ energy pyramid. The shape of an energy pyramid shows that the amount of food energy that enters each trophic level is less than the amount that entered the level below. Approximately 90 percent of the food energy that enters a trophic level is “lost” as heat when it is used by organisms to power the normal activities of life such as breathing and digesting food the remaining 10 percent is stored in the various organisms’ tissues.

It is this latter energy that is available to be passed to the next trophic level. Thus, the higher the trophic level on the pyramid, the lower the amounts of available energy ecosystem energy transfer through an ecosystem. The number of organisms at each level decreases relative to the level below because there is less energy available to support those organisms. The top level of an energy pyramid has the fewest organisms because it has the least amount of energy. Eventually there is not enough energy left to support another trophic level; thus most ecosystems only have four trophic levels.

Balbharati Maharashtra State Board 9th Std Science Textbook Solutions

• Laws of Motion Class 9 Science Textbook Solutions
• Work and Energy Class 9 Science Textbook Solutions
• Current Electricity Class 9 Science Textbook Solutions
• Measurement of Matter Class 9 Science Textbook Solutions
• Acids, Bases and Salts Class 9 Science Textbook Solutions
• Classification of Plants Class 9 Science Textbook Solutions
• Energy Flow in an Ecosystem Class 9 Science Textbook Solutions
• Useful and Harmful Microbes Class 9 Science Textbook Solutions
• Environmental Management Class 9 Science Textbook Solutions

Std 9 Science Chapter 5 Acids, Bases and Salts Question Answer Maharashtra Board

Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 5 Acids, Bases and Salts Notes, Textbook Exercise Important Questions and Answers.

Class 9 Science Chapter 5 Acids, Bases and Salts Question Answer Maharashtra Board

Class 9 Science Chapter 5 Acids, Bases and Salts Textbook Questions and Answers

1. Identify the odd one out and justify.

(a) Chloride, nitrate, hydride, ammonium
Answer:
Ammonium is the odd one out as it is a basic radical and rest all are acidic radicals. Generally, basic radicals are formed by the removal of electrons from the atom of metals such as Na⁺, Cu²⁺. But there are some exceptions, such as NH₄⁺.

(b) Hydrogen chloride, sodium hydroxide, calcium oxide, ammonia
Answer:
Hydrogen chloride is the odd one out. It is acidic and rest all are basic.

(c) Acetic acid, carbonic acid, hydrochloric acid, nitric acid
Answer:
Carbonic acid is the odd one out. It is a dibasic acid and rest are all monobasic acids.

(d) Ammonium chloride, sodium chloride, potassium nitrate, sodium sulphate
Answer:
Ammonium chloride is the odd one out, as it is made up of a strong acid and weak base and rest all are formed from strong acid and strong base.

(e) Sodium nitrate, sodium carbonate, sodium sulphate, sodium chloride
Answer:
Sodium carbonate is the odd one out, as it is made up of a weak acid and strong base, and rest all are formed from strong acid and strong base.

(f) Calcium oxide, magnesium oxide, zinc oxide, sodium oxide.
Answer:
Zinc oxide is the odd one out, as it is an amphoteric oxide, and rest all are basic oxides.

(g) Crystalline blue vitriol, crystalline common salt, crystalline ferrous sulphate, crystalline sodium carbonate.
Answer:
Crystalline common salt is the odd one out, as it does not contain water of crystallisation. It is an ionic compound and ionic compounds are crystalline in nature and rest all have their crystalline structure because of their water of crystallization.

(h) Sodium chloride, potassium hydroxide, acetic acid, sodium acetate.
Answer:
Acetic acid is the odd one out. It is an acid, the rest are all salts.

2. Write down the changes that will be seen in each instance and explain the reason behind it.

(a) 50ml water is added to 50ml solution of copper sulphate.

Answer:

• Copper sulphate solution is blue. It is a concentrated solution.
• When 50 ml of water is added to this concentrated solution, it becomes a diluted solution.
• The intensity of the blue colour is now different in this homogenous mixture.

(b) Two drops of the indicator phenolphthalein were added to 10ml solution of sodium hydroxide.

Answer:

• Sodiumhy droxide is a base and phenolphthalein is a synthetic indicator.
• Sodium hydroxide solution will turn pink if phenolphthalein is added to it.
• It is a test for identifying bases.

(c) Two or three filings of copper were added to 10ml dilute nitric acid and stirred.
Answer:
When copper metal reacts with dilute nitric acid, the metal does not displace hydrogen from the acid like reaction with other metals. Instead the reaction produces nitric oxide, (NO).

(d) A litmus paper was dropped into 2ml dilute HCl. Then 2ml concentrated NaOH was added to it and stirred.
Answer:
Blue litmus Paper:

• HCl is hydrochloric acid, so the blue litmus turns red.
• When equal amount of NaOH is added the colour again changes to blue and remains the same.

Red litmus paper:

• Red litmus paper shows no colour change in hydrochloric acid.
• When some amount of NaOH is added the colour changes to blue initially but when the amount of NaOH is sufficient the blue colour dissappears.
• Equal amounts of HC1 and NaOH results in the formation of NaCl, a salt, and the solvent water. This reaction is called the neutralization reaction.

(e) Magnesium oxide was added to dilute HCl and magnesium oxide was a added to dilute NaOH.
Answer:
(i) Magnesium oxide + dil HCl.
This is a neutralization reaction. Magnesium oxide is an insoluble base, it reacts with dilute HCl to produce a soluble salt MgCl₂ and water H₂O.
\(\mathrm{MgO}_{(\mathrm{s})}+2 \mathrm{HCl}_{(\mathrm{aq})} \longrightarrow \mathrm{MgCl}_{2(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}_{(n)}\)

(ii) Magnesium oxide + NaOH.
No chemical reaction takes place between magnesium oxide and sodium hydroxide.

(f) Zinc oxide was added to dilute HCl and zinc oxide was added to dilute NaOH.
Answer:

• Zinc oxide reacts with dilute hydrochloric acid to form zinc chloride and water. It is a neutralization reaction.
  \(\mathrm{ZnO}_{(\mathrm{s})}+2 \mathrm{HCl}_{(\mathrm{aq})} \longrightarrow \mathrm{ZnCl}_{2(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})}\)
• Zinc oxide reacts with sodium hydroxide to form sodium zincate and water.
  \(\mathrm{ZnO}_{(\mathrm{s})}+2 \mathrm{NaOH}_{(\mathrm{aq})} \longrightarrow \mathrm{Na}_{2} \mathrm{ZnO}_{2(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}_{(\mathrm{t})}\)

(g) Dilute HCl was added to limestone.
Answer:

• When hydrochloric acid is added to limestone, carbon dioxide is liberated. Limestone is calcium carbonate.
  CaCO₃ + 2 HCl → CaCl₂ + CO₂ + H₂O
• Carbon dioxide is prepared in the laboratory using these chemicals.

(h) Pieces of blue vitriol were heated in a test tube. On cooling, water was added to it.
Answer:

• On heating, the crystalline structure of blue vitriol breaks down to form a colourless powder and water is released.
• This water is part of the crystal structure of blue vitriol.
• It is called water of crystallization.
• On adding water to the white powder, a solution was formed which has the same colour as the copper sulphate salt solution.

(i) Dilute H₂SO₄ was taken in an electrolytic cell and electric current was passed through it.
Answer:

• If pure water is used in the electrolytic cell, current does not flow even on putting on the switch.
• Pure water is a bad conductor of electricity. Dilute H₂SO₄ is acidulated water.
• The electrical conductivity of water increases on mixing with strong acid or base in it due to their dissociation and electrolysis of water takes place.
• H₂SO₄ is fully dissociated in aqueous solution. \(\mathrm{H}_{2} \mathrm{SO}_{4} \longrightarrow 2 \mathrm{H}^{+}+\mathrm{SO}_{4}^{2-}\)
• H₂O is a weak electrolyte and is only slightly dissociated \(\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{H}^{+}+\mathrm{OH}^{-}\)
• During electrolysis, the hydrogen ions migrate towards the cathode and are discharged there.

[H+ ions gains electrons and are converted to hydrogen gas]
\(2 \mathrm{H}^{+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2(\mathrm{~g})}\)
Cathode reaction:
\(2 \mathrm{H}_{2} \mathrm{O}_{(\mathrm{i})}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2(\mathrm{~g})}+2 \mathrm{OH}_{(\mathrm{aq})}^{-}\)
Anode reaction:
\(2 \mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})} \longrightarrow \mathrm{O}_{2(\mathrm{~g})}+4 \mathrm{H}_{(\mathrm{aq})}^{+}+4 \mathrm{e}\)

• For every hydrogen ion discharged at the anode, another hydrogen ion is formed at the cathode.
• The net result is that the concentration of the sulphuric acid remains constant and electrolysis of water is overall reaction. \(2 \mathrm{H}_{2} \mathrm{O} \longrightarrow 2 \mathrm{H}_{2}+\mathrm{O}_{2}\)
• The volume of the hydrogen gas formed near the cathode is double that of the oxygen gas formed near the anode.

3. Classify the following oxides into three types and name the types.
CaO, MgO, CO₂, SO₃, Na₂O, ZnO, Al₂O₃, Fe₂O₃
Answer:
There are three types of oxides : Basic oxides, Acidic oxides and Amphoteric oxides.

Generally metal oxides are basic in nature.
Exception : Al₂O₃ and ZnO are amphoteric oxides.
Generally non-metal oxides are acidic in nature.

4. Explain by drawing a figure of the electronic configuration.

a. Formation of sodium chloride from sodium and chlorine.
Answer:

b. Formation of a magnesium chloride from magnesium and chlorine.
Answer:

5. Show the dissociation of the following compounds on dissolving in water, with the help of chemical equation and write whether the proportion of dissociation is small or large.
Hydrochloric acid, Sodium chloride, Potassium hydroxide, Ammonia, Acetic acid, Magnesium chloride, Copper sulphate.
Answer:
(a) Hydrochloric acid (HCl)

• \(\mathrm{HCl}_{(g)} \frac{\text { Water }}{\text { dissociation }}>\mathrm{H}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{(\mathrm{aq})}^{-}\)
• Hydrochloric acid is a strong acid, as on dissolving in water, it dissociates almost completely and the resulting aqueous solution contains mainly H ions and the concerned acidic radical.
• The proportion of dissociation is large.

(b) Sodium chloride (NaC1)

• \(\mathrm{NaCl}_{(s)} \frac{\text { Water }}{\text { dissociation }}>\mathrm{Na}_{(\mathrm{aq})}^{+}+\mathrm{Cl}_{\text {(aq) }}^{-}\)
• When an ionic compound begins to dissolve in water, the water molecules push themselves in between the positive and negative ions of the compound and separate them from each other.
• The proportion of dissociation is large.

(c) Potassium hydroxide (KOH)

• \(\mathrm{KOH}_{(n)} \frac{\text { Water }}{\text { dissociation }} \mathrm{K}_{(\mathrm{aq})}^{+}+\mathrm{OH}_{(\mathrm{aq})}\)
• Potassium hydroxide is a strong base, as on dissolving in water, it dissociates almost completely and the resulting aqueous solution contains mainly OH⁺ ions and the concerned basic radical.
• The proportion of dissociation is large.

(d) Ammonia (NH₃)
(i) \(\mathrm{NH}_{3(\mathrm{~g})}+\mathrm{H}_{2} \mathrm{O}_{(\mathrm{n}}-\frac{\text { Water }}{\text { uissociation }}>\mathrm{NH}_{4 \text { (aq) }}^{+}+\mathrm{OH}_{\text {(aq) }}^{-}\)
(ii) Ammonia dissolves in water to form NH₄OH (ammonium hydroxide). NH₄OH does not dissociate completely as it is a weak base. The aqueous solution contains a small proportion of OH^– ions and the concerned basic radical along with a large proportion of undissociated molecules of the base i.e. NH₄OH.
(iii) The proportion of dissociation is small.

(e) Acetic acid (CH₃COOH)

• \(\mathrm{CH}_{3} \mathrm{COOH}_{(l)} \frac{\text { Water }}{\text { dissociation }} \mathrm{CH}_{3} \mathrm{COO}_{(\text {aq) }}+\mathrm{H}_{(a z)}+{ }^{+}\)
• Acetic acid is a weak acid, on dissolving in water it does not dissociate completely, and the resulting aqueous solution contains H⁺ ion and the concerned acidic radical in small proportion along with large proportion of the undissociated molecules of the acid.
• The proportion of dissociation is small.

(f) Magnesium chloride (MgCl₂)

• \(\mathrm{MgCl}_{2(\mathrm{~s})} \frac{\text { Water }}{\text { dissociation }}>\mathrm{Mg}^{2+} \text { (aq) }+2 \mathrm{Cl}^{-} \text {(aq) }\)
• Magnesium chloride dissolves in water and forms magnesium ions and chloride ions. When an ionic compound begins to dissolve in water, the water molecules push themselves in between the ions of the compound and separate them from each other.
• The proportion of dissociation is large.

(g) Copper sulphate (CuSO₄)

• \(\mathrm{CuSO}_{4(s)} \frac{\text { Water }}{\text { dissociation }}>\mathrm{Cu}_{(\mathrm{aq})}^{2+}+\mathrm{SO}_{4}^{2-}\)
• When Copper sulphate is dissolved in water it forms copper ions and sulphate ions. When an ionic compound begins to dissolve in water, water molecules push themselves in between the ions of the compound and separate them from each other.
• The proportion of dissociation is large.

6. Write down the concentration of each of the following solutions in g/L and mol/L.

a. 7.3g HCl in 100ml solution
b. 2g NaOH in 50ml solution
c. 3g CH₃COOH in 100ml solution
d. 4.9g H₂SO₄ in 200ml solution
Answer:
To find : The concentration in g/L.
Solution:

7. Obtain a sample of rainwater. Add to it a few drops of universal indicator. Meausre its pH. Describe the nature of the sample of rainwater and explain the effect if it has on the living world.
Answer:

• pH of rain water is 6.5 that means rain water is slightly acidic.
• When we add universal indicator to rain water it turns orangish red, indicating pH value is between 0 to 7, which tells us that rain water is acidic in nature.
• Most of the plants grow best when pH of soil is close to 7. If the soil is too acidic or too basic, it affects plant growth.

8. Answer the following questions.

a. Classify the acids according to their basicity and give one example of each type.
Answer:

• Basicity of acids : The number of H⁺ ions obtainable by the dissociation of one molecule of an acid is called its basicity. The acids are classified as monobasic, dibasic and tribasic acids based on the number of H⁺ ions present.
• Examples of monobasic acid : HCl, HNO₃, CH₃COOH
• Examples of dibasic acid: H₂SO₄, H₂CO₃
• Examples of tribasic acid: H₃BO₃, H₃PO₄

b. What is meant by neutralization? Give two examples from everyday life of the neutralization reaction.
Answer:

• In neutralization reaction, an acid reacts with a base to form salt and water.
• In a neutralisation reaction the acid dissociates to form H⁺ ions and base dissociates to form OH ions.
• They combine to form H₂O molecules which mixes with the solvent.

Examples in daily life:

• When people suffer from acidity, they take some antacids to neutralise the acid in their stomach.
• If an ant stings us the pain is due to formic acid. It is neutralised by rubbing moist baking soda which is basic in nature.

c. Explain what is meant by electrolysis of water. Write the electrode reactions and explain them.
Answer:
Electrolysis of water:

• Electrolysis of water is the decomposition of water into oxygen and hydrogen gas due to an electric current being passed through acidified water.
• Cathode reaction:
  \(2 \mathrm{H}_{2} \mathrm{O}_{(l)}+2 \mathrm{e}^{-} \longrightarrow \mathrm{H}_{2(\mathrm{~g})}+2 \mathrm{OH}_{(\mathrm{aq}}\)
• Anode reaction:
  \(2 \mathrm{H}_{2} \mathrm{O}_{(l)} \longrightarrow \mathrm{O}_{2(\mathrm{~g})}+4 \mathrm{H}_{(\mathrm{aq})}^{+}+4 \mathrm{e}^{-}\)
• It is found that the volume of gas formed near the cathode is double that of the gas formed near the anode.
• Hydrogen gas is formed near the cathode and oxygen gas near the anode.
• From this, it is clear that electrolysis of water has taken place and its constituent element have been released.

9. Give a reason for the following.

a. Hydronium ions are always in the form H₃O⁺.
Answer:

• Acids in water gives H⁺ ions. These H⁺ ions do not exist freely in water.
• This is because H⁺ is a single proton, a hydrogen atom has only one proton and one electron.
• If the electron is removed to make H⁺, all that is left is an extremely tiny positively charged nucleus.
• This H ion will immediately combine with the surrounding water (H₂O) molecules to form (H₃O₄) hydronium ion.

b. Buttermilk spoils if kept in a copper or brass container.
Answer:

• Buttermilk contains an organic acid called as lactic acid.
• The lactic acid reacts with copper and brass and forms toxic compounds which are not fit for consumption.
• They are harmful and may cause food poisoning.
• So it is not advisable to keep buttermilk in brass or copper containers.

10. Write the chemical equations for the following activities.

(a) NaOH solution was added to HCl solution.
Answer:
When NaOH reacts with HCl, it gives NaCl and water.

(b) Zinc dust was added to dilute H₂SO₄.
Answer:
When zinc reacts with dilute sulphuric acid, it forms zinc sulphate and hydrogen gas is liberted.

(c) Dilute nitric acid was added to calcium oxide.
Answer:
When dilute nitric acid reacts with calcium oxide, it forms calcium nitrate and water.

(e) Carbon dioxide gas was passed through KOH solution.

(f) Dilute HCl was poured on baking soda.

11. State the differences.

a. Acids and bases
Answer:

b. Cation and anion
Answer:

c. the Negative electrode and the positive electrode.

Answer:

12. Classify aqueous solutions of the following substances according to their pH into three groups : 7, more than 7, less than 7.

Common salt, sodium acetate, hydrochloric acid, carbon dioxide, potassium bromide, calcium hydroxide, ammonium chloride, vinegar, sodium carbonate, ammonia, sulphur dioxide.
Answer:

Class 9 Science Chapter 5 Acids, Bases and Salts Intext Questions and Answers

Question 1.
How are the following substances classified into three groups with the help of litmus?
Lemon, tamarind, baking soda, buttermilk, vinegar, orange, milk, lime, tomato, milk of magnesia, water, alum.
Answer:

Question 2.
Fill in the columns in the part of the following table:
Answer:

Question 3.
Complete the following table of the concentration of various aqueous solutions.
Answer:

Question 4.
Complete the following table of neutralization reactions and also write down the names of the acids, bases and salts in it.
Answer:

Question 5.
What are the names of the following compounds? NH₃, Na₂O, CaO.
Answer:
NH₃ : Ammonia
Na₂O : Sodium oxide
CaO : Calcium oxide

Question 6.
Into which type will you classify the above compounds, acid, base or salt?
Answer:
NH₃ : base
Na₂O : base
CaO : base

Question 7.
ive examples of monobasic, dibasic and tribasic acids.
Answer:
Monobasic acid examples: HNO₃, HCl, CH₃COOH
Dibasic acid examples: H₂SO₄, H₂CO₃
Tribasic acid examples: H₃BO₃, H₃PO₄

Question 8.
Give the three types of bases with their examples.
Answer:
Types of bases:
Monoacidic base examples : NaOH, KOH, NH₄OH
Diacidic base examples: Ca(OH)₂, Ba(OH)₂
Triacidic base examples: A(OH)₃, Fe(OH)₃

Question 9.
What are the colours of the following natural and synthetic indicators in acidic and basic solutions? Litmus, turmeric, jamun, methyl orange, phenolphthalein?
Answer:

Question 10.
On mixing the substances as shown here, what are the resulting mixtures formed by mixing the following substances called?
(a) Water and salt
(b) Water and sugar
(c) Water and sand
(d) Water and sawdust
Answer:
(a) Water and salt – Homogeneous mixture
(b) Water and sugar – Homogeneous mixture
(c) Water and sand – Heterogeneous mixture
(d) Water and sawdust – Heterogeneous mixture

Question 11.
What would be the definition of an acid and a base with reference to the neutralization reaction?
Answer:

• Acid: An acid is a substance which neutralises a base to form salt and water.
• Base: A base is a substance which neutralises an acid to form salt and water.

Answer the following questions:

Question 1.
Take aqueous solution of sodium chloride, copper sulphate, glucose, urea, dil.H₂SO₄ and dil.NaOH in a beaker and test the electrical conductivity of the solutions. Answer the given below questions.

(a) With which solutions did the bulb glow?
Answer:
Solutions with which bulb glows: Aqueous solution of NaCl, CuSO₄, H₂SO₄ and NaOH.

(b) Which solutions are electrical conductors?
Answer:
Solutions which are electrical conductors:
NaCl, CuSO₄, H₂SO₄ and NaOH.

Question 2.
During electrolysis of copper sulphate, if electric current is passed through the electrolytic cell for a long time, what change would be seen at the anode?
Answer:

• When electricity is passed for a long time through copper sulphate solution, the following reaction is seen at the anode: Anode Reaction: Cu(s) → Cu²⁺(aq) + 2e^–
• All the copper atoms will get converted into copper ions and get deposited on the cathode. This process continues till the copper anode exists.

Question 3.
Would water be a good conductor of electricity?
Answer:
Pure water is not a good conductor of electricity.

Answer the following questions:

Question 1.
(i) With which solutions did the bulb glow?
(ii) Which solutions are electrical conductors?

Answer:
(i) The bulbs glows when the wire are immersed in NaCl solution.
(ii)

Question 2.
What would be the definition of an acid and a base with reference to the neutralization reaction?
Answer:

• Acid: An acid is a substance which neutralises a base to form salt and water.
• Base: A base is a substance which neutralises an acid to form salt and water.

Question 3.
Dissolve 2g salt in 500ml pure water. Take 250 ml of this solution in a 500ml capacity beaker. Connect two electrical wires to the positive and negative terminals of a power supply. Remove the insulating cladding from about 2cm portions at the other ends of the wires. These are the two electrodes. Fill two test tubes upto the brim with the prepared dilute salt solution. Invert them on the electrodes without allowing any air to enter. Start the electric current under 6V potential difference from the power supply. Observe what happens in the test tubes after some time.
(a) Did you see the gas bubbles forming near the electrodes in the test tubes?
(b) Are these gases heavier or lighter than water?
(c) Are the volumes of the gases collected over the solution in the two test tubes the same or different?
(d) Test the solutions in the two test tubes with litmus paper, what do you see?
(e) Repeat the activity by using dilute H₂SO₄ as well as dilute NaOH as the electrolyte.
Answer:
(a) Yes, gas bubbles can be seen forming near the electrodes in the test tube.
(b) These gases are lighter than water.

(c) The volumes of gases collected over the solution in the two test tubes are different.
(d) The solution in the cathode turns red litmus blue while solution in anode turns blue litmus red.
(e) When the above experiment is repeated with dil H₂SO₄ and dil NaOH, Hydrogen gas is liberated at cathodes and oxygen gas is liberated at anode.

Answer the following questions:

Question 1.
Cut a lemon into two equal parts. Take the juice of each part into two separate beakers. Pour 10 ml of drinking water in one beaker and 20 ml in the second. Stir the solutions in both the beakers and taste them. Is there any difference in the tastes of the solutions in the two beakers? What is that difference?
Answer:

• In the above activity, the sour taste of the solutions is because of the solute, lemon juice in them.
• The quantity of the lemon juice is the same in both the solutions. Yet their tastes are different.
• The solution in the first beaker is more sour than the one in the second.
• Although the quantity of the solute is the same in both the solutions, the quantity of the solvent is different.
• Ratio of the quantity of the solute to the quantity of the resulting solution is different. This ratio is larger for the solution in the first beaker and therefore that solution tastes more sour.
• On the other hand, the proportion of the lemon juice in the total solution in the second beaker is smaller and taste is less sour.
• The taste of foodstuff depends upon the nature of the taste-giving ingredient and its proportions in the foodstuff.
• Similarly, all the properties of a solution depend on the nature of the solute and solvent and also on the proportion of the solute in a solution
• The proportions of a solute in a solution is called the concentration of the solute in the solution.

Question 2.
Take a big test tube. Choose a rubber stopper in which a gas tube can be fitted. Take a few pieces of magnesium ribbon in the test tube and add some dilute HCl to it. Take a lighted candle near the end of the gas tube and observe. What did you observe?

Answer:

• Magnesium metal reacts with dilute HCl and an inflammable gas, hydrogen, is formed.
• During this reaction, the reactive metal displaces hydrogen from the acid to release hydrogen gas.
• At the same time, the metal is converted into basic radical which combines with the acidic radical from the acid to form the salt.
  \(\mathrm{Mg}_{(\mathrm{s})}+2 \mathrm{HCl}_{(\mathrm{aq}) \longrightarrow} \underset{\rightarrow}{\mathrm{MgCl}_{2(\mathrm{aq})}}+\mathrm{H}_{2(\mathrm{~g})}\)

Question 3.
Take some water in a test tube and add a little red oxide (the primer used before painting iron articles) to it. Now add a small quantity of dilute HCl to it, shake the test tube and observe.
(a) Does the red oxide dissolve in water?
(b) What change takes place in the particles of red oxide on adding dilute HCl?
Answer:
(a) The chemical formula of red oxide is Fe₂O₃. It is insoluble in water.
(b) The water-insoluble red oxide reacts with HCl to produce a water-soluble salt FeCl₃.

• This gives a yellowish colour to the water.
• The following chemical equation can be written for this chemical change.
  \(\mathrm{Fe}_{2} \mathrm{O}_{3(\mathrm{~s})}+6 \mathrm{HCl}_{(\mathrm{aq})} \longrightarrow 2 \mathrm{FeCl}_{3(\mathrm{aq})}+3 \mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})}\)

Question 4.
Fit a bent tube in a rubber cork. Take some lime water in a test tube and keep it handy. Take some baking soda in another test tube and add some lemon juice to it. Immediately fit the bent tube over it. Insert its other end into the lime water. Note down your observations of both the test tubes. Repeat the procedure using washing soda, vinegar and dilute HC1 properly. What do you see?
Answer:

• In this activity, when limewater comes in contact with the gas released in the form of an effervescence, it turns milky.
• This is a chemical test for carbon dioxide gas.
• When lime water turns milky, we infer that the effervescence is of CO₂.
• This gas is produced on the reaction of acids with carbonate and bicarbonate salts of metals.
• A precipitate of CaCO₃ is produced on its reaction with the lime water Ca(OH)₂.
• This reaction can be represented by the following chemical equation.
  \(\mathrm{Ca}(\mathrm{OH})_{2(\mathrm{aq})}+\mathrm{CO}_{2(\mathrm{~g})} \longrightarrow \mathrm{CaCO}_{3(\mathrm{~s})}+\mathrm{H}_{2} \mathrm{O}_{(\mathrm{l})}\)
• Washing soda is sodium carbonate Na2CO₃. It will react same as baking soda (NaHCO₃).
• Vinegar and HCl are acids, they do not react chemically with lemon juice.

Class 9 Science Chapter 5 Acids, Bases and Salts Additional Important Questions and Answers

Select the correct option

Question 1.
…………………. acid is present in lemon.
(a) malic acid
(b) tartaric acid
(c) citric acid
(d) butyric acid
Answer:
(c) Citric acid

Question 2.
Tamarind contains …………………. acid.
(a) Lactic acid
(b) tartaric acid
(c) matlic acid
(d) butyric acid
Answer:
(b) tartaric

Question 3.
Butter milk contains …………………. acid.
(a) butyric acid
(b) Lactic acid
(c) matlic acid
(d) citric acid
Answer:
(a) Butyricacid

Question 4.
If the basic radical is H+ the type of compound is ………………… .
(a) neutral
(b) base
(c) acid
(d) alkali
Answer:
(c) Acid

Question 5.
The name of compound NH3 is ………………… .
(a) nitric acid
(b) ammonium
(c) nitride
(d) ammonia
Answer:
(b) ammonia

Question 6.
The bases which are soluble in water are called as ………………… .
(a) indicators
(b) acids
(c) alkalis
(d) salts
Answer:
(c) alkalis

Question 7.
H₃PO₄ is a …………………. acid.
(a) monobasic
(b) tribasic
(c) tetrabasic
(d) dibasic
Answer:
(b) tribasic

Question 8.
According to pH scale pure water has a pH of ………………… .
(a) 6
(b) 7
(c) 5
(d) 8
Answer:
(b) 7

Question 9.
With reference to neutralization, metallic oxides are ………………… in nature.
(a) basic
(b) neutral
(c) acidic
(d) saline
Answer:
(a) basic

Question 10.
Molecular formula of blue vitriol is ………………… .
(a) CuSO₃ 5H₂O
(b) CuSO₄ 4H₂O
(c) CUSO₃ 4H₂O
(d) CUSO₄ 5H₂O
Answer:
(d) CUSO₄ 5H₂O

Question 11.
Molecular formula of crystalline alum is ………………… .
(a) KSO₄, AISO₄, 24H₂O
(b) K₂SO₄, ALSO₄, 24H₂O
(c) K₂SO₄, AL₂(SO₄)₃, 24H₂O
(d) KSO₄, Al₂(SO₄)₃, 24H₂O
Answer:
(c) K₂SO₄, AL₂(SO₄)₃, 24H₂O

Question 12.
Molecular formula for sodium oxide is ………………… .
(a) Na₂O
(b) NaO₂
(c) NaO
(d) Na₂O₂
Answer:
(a) Na₂O

Question 13.
H₂CO₃ is …………………. acid.
(a) monobasic
(b) dibasic
(c) tribasic
(d) tetrabasic
Answer:
(b) dibasic

Question 14.
Molecular formula of Red oxide is ………………… .
(a) Fe₂O₃
(b) CuO
(c) Fe₃O₄
(d) Na₂O
Answer:
(a) Fe₂O₃

Question 15.
The positive terminal electrode is called as ………………… .
(a) anode
(b) cathode
(c) anion
(d) cation
Answer:
(a) anode

Question 16.
…………………. produced in stomach helps in digestion.
(a) Hydrochloric acid
(b) Oxalic acid
(c) Sulphuric acid
(d) Nitric acid?
Answer:
(a) Hydrochloric acid

Question 17.
The solution turns blue litmus red, its pH is likely to be ………………… .
(a) 7
(b) 4
(c) 14
(d) 9
Answer:
(b) 4

Question 18.
An ionic compound NaCl is formed by ………………… .
(a) Na⁺ and Cl^–
(b) Na⁺ and Cl⁺
(c) Na^– and Cl^–
(d) Na^– and Cl⁺
Answer:
(a) Na⁺ and Cl^–

Question 19.
pH of strong acid is ………………… .
(a) 0
(b) 7
(c) 8
(d) 14
Answer:
(a) 0

Question 20.
HCl + NaOH → NaCl + H₂O is a …………………. reaction.
(a) neutralization
(b) crystallisation
(c) electrolysis
(d) dissociation
Answer:
(a) neutralization

Question 21.
Adding water to acid is an …………………. reaction.
(a) endothermic
(b) exothermic
(c) neutralisation
(d) crystallisation
Answer:
(b) exothermic

Find the odd one out:

(a) Rose Petal, Turmeric, Phenolphthalein, Indigo.
Answer:
Phenolphthalein is odd one out as rest are natural indicators while phenolphthalein is a synthetic indicator.

(b) Lime water, Vinegar, Acetic acid, Tartaric acid.
Answer:
Lime water is odd one out as this is basic in nature while rest are acidic.

(c) NaHCO₃, HCl, H₂SO₄, HNO₃
Answer:
NaHCO₃ is odd one out as it is base while rest are acids.

(d) Oxalic acid, Nitric acid, Citric acid, acetic acid.
Answer:
Nitric acid is odd one out as others are weak acids while Nitric acid is a strong acid.

(e) Crystalline, Liquid, Gases, Solid.
Answer:
Crystalline is odd one out as this is nature of a compound while others are physical states of compounds.

(f) Ca(OH)₂, Mg (OH)₂, NaOH, NH₄OH.
Answer:
NaOH is odd one out even though all are bases but NaOH is highly soluble in water compared to others.

Name the following:

Question 1.
Name the three types of ionic compounds.
Answer:
The three types of ionic compounds are acids, bases and salts.

Question 2.
Name the two constituents of molecule of an ionic compound.
Answer:

• Cation (positive ion/ basic radical)
• Anion (negative ion/acidic radical).

Question 3.
Name any three acids with their molecular formula.
Answer:

• Hydrochloric acid – HC1
• Sulphuric acid – H₂SO₄
• Nitric acid – HNO₃

Question 4.
Name any three bases with their molecular formula.
Answer:

• Sodium hydroxide – NaOH
• Potassium hydroxide – KOH
• Calcium hydroxide – Ca(OH)₂

Question 5.
Name any three salts with their molecular formula.
Answer:

• Sodium chloride – NaCl
• Potassium sulphate – K₂ SO₄
• Calcium chloride – CaCl₂

Question 6.
Name any two strong acids.
Answer:

• Hydrochloric acid – HC1
• Sulphuric acid – H₂ SO₄

Question 7.
Name any two weak acids.
Answer:

• Acetic acid – CH₃ COOH
• Carbonic acid – H₂ CO₃

Question 8.
Name any two strong bases.
Answer:

• Sodium hydroxide – NaOH
• Potassium hydroxide – KOH

Question 9.
Name a weak base.
Answer:
Ammonium hydroxide – NH₄OH

Question 10.
Name any two alkalis.
Answer:

• Sodium hydroxide – NaOH
• Potassium hydroxide – KOH

Question 11.
Name any two acids with their basicity 1 (monobasic)
Answer:

• Hydrochloric acid – HC1
• Nitric acid – HNO₃

Question 12.
Name any two acids with their basicity 2 (dibasic)
Answer:

• Sulphuric acid – H₂ SO₄
• Carbonic acid – H₂CO₃

Question 13.
Name any two acids with their basicity 3 (tribasic)
Answer:

• Boric acid – H₃BO₃
• Phosphoric acid – H₃PO₄

Question 14.
Name any two bases with their acidity 1 (monoacidic)
Answer:

• Sodium hydroxide – NaOH
• Potassium hydroxide – KOH

Question 15.
Name any two bases with their acidity 2 (diacidic)
Answer:

• Calcium hydroxide – Ca(OH)₂
• Barium hydroxide – Ba(OH)₂

Question 16.
Name any two bases with their acidity 3 (triacidic)
Answer:

• Aluminium hydroxide – Al(OH)₃
• Ferric hydroxide – Fe(OH)₃

Question 17.
Name the two units to express the concentration of the solution.
Answer:

• mass of solute in grams dissolved in one litre of the solution grams per litre, (g/L).
• Number of moles of the solute dissolved in one litre of the solution. Molarity (M) of the solution.

Match the columns:

Question 1.

Answer:
(1-d),
(2- c),
(3 – a),
(4 – b)

Question 2.

Answer:
(1-d),
(2- c),
(3 – a),
(4 – b)

Question 3.

Answer:
(1-d),
(2- c),
(3 – a),
(4 – b)

Question 4.

Answer:
(1 – b),
(2 – c),
(3 – d),
(4 – a)

Question 5.

Answer:
(1-c),
(2- a),
(3 – d),
(4 – b)

State whether the following statements are true or false and if false. Correct the false statement:

(1) The separation of H and CI in HCI is in absence of water.
(2) \(\mathrm{NaOH}_{(\mathrm{s})} \frac{\text { Water }}{\text { dissociation }}>\mathrm{Na}_{(\mathrm{aq})}^{+}+\mathrm{OH}_{(\mathrm{aq})}^{-}\)
(3) H₂SO₄ is a strong acid.
(4) NaC1 is an ionic compound.
(5) Turmeric is synthetic indicator.
(6) Metal + Dilute acid forms salt and water.
(7) Copper oxide is called red primer.
(8) Oxide of non-metal + Acid → Salt + Water.
(9) Zinc oxide reacts with sodium hydroxide to form sodium zincate.
(10) Al₂O₃ is an amphoteric oxide.
(11) Blue vitriol ZnSO₄. 7H₂O.
(12) Molecular formula for crystalline Ferrous sulphate is Fe5O₄. 5H₂O.
(13) NaCl in water does not conduct electricity.
(14) Phenolphthalein is colourless in base.
Answer:
(1) False. The separation of H⁺ and Cl^– in HC1 is in presence of water.
(2) True
(3) True
(4) True
(5) False. Turmeric is a natural indicator.
(6) False. Metal + Dilute acid forms salt and hydrogen gas.
(7) False. Iron oxide is called red primer.
(8) False. Oxide of izan-metal + Base → Salt + Wafer.
(9) True
(10) True
(11) False. Blue Vitriol is CuSO₄. 5H₂O.
(12) False. Molecular formula for crystalline Ferrous sulphate is FeSO₄. 7H₂O.
(13) False. NaCl in water conducts electricity.
(14) False, Phenolphthalein is colourless in acid and pink in base.

Define the following:

Question 1.
Acid
Answer:
An acid is a substance which on dissolving in water gives rise to H ion as the only cation. For example, HC1, H₂ SO₄, H₂CO₃.

Question 2.
Base
Answer:
A base is a substance which on dissolving in water gives rise to the OW ion as the only anion. For, NaOH, Ca(OH)₂

Question 3.
Strong Acid
Answer:
On dissolving in water, a strong acid dissociates almost completely, and the resulting aqueous solution contains mainly H ions and the concerned acidic radical. e.g. HC1, HBr, HNO₃, H₂SO₄.

Question 4.
Weak Acid
Answer:
On dissolving in water a weak acid does not dissociate completely, and the resulting aqueous solution contains H+ ion and the concerned acidic radical in small proportion along with large proportion of the undissociated molecules of the acid, e.g., H₂CO₃ (Carbonic acid), CH₃COOH (Acetic acid)

Question 5.
Strong Base
Answer:
On dissolving in water, a strong base dissociates almost completely and the resulting aqueous solution contains mainly OH ions and the concerned basic radicals, e.g. NaOH, KOH, Ca(OH)₂, Na₂O.

Question 6.
Weak Base
Answer:
On dissolving in water, a weak base does not dissociate completely and the resulting aqueous solution contains a small proportion of OH ions and the concerned basic radical along with a large proportion of undissociated molecules of the base. e.g. NH₄ OH.

Question 7.
Alkali
Answer:
The bases which are highly soluble in water are called alkali, e.g. NaOH, KOH, NH3. Here, NaOH and KOH are strong alkalis while NH₃ is a weak alkali.

Question 8.
Basicity of acids
Answer:
The number of H⁺ ions obtainable by the dissociation of one molecule of an acid is called its basicity.

Question 9.
Acidity of bases
Answer:
The number of OH ions obtainable by the dissociation of one molecule of a base is called its acidity.

Question 10.
Concentration of solute in the solution.
Answer:
The proportion of a solute in a solution is called the concentration of the solute in the solution.

Question 11.
Concentrated solution.
Answer:
When the concentration of a solute in its solution is high, it is a concentrated solution.

Question 12.
Dilute solution
Answer:
When the concentration of a solute in its solution is low, it is a dilute solution.

Question 13.
Neutralization
Answer:
A reaction in which an acid reacts with a base to form salt and water is called a neutalization reaction.
NaOH + HC1 → NaCl + H₂O
Base + Acid → Salt + Water

Question 14.
Cathode
Answer:
The electrode connected to the negative terminal of a battery by means of a conducting wire is called a cathode.

Question 15.
Anode
Answer:
The electrode connected to the positive terminal of a battery by means of a conducting wire is called an anode.

Question 16.
Cations
Answer:
Cations are positively charged ions which are attracted towards negative electrode (cathode) when electricity is passed into a solution of an ionic compound.

Question 17.
Anions
Answer:
Anions are negatively charged ions which are attracted towards the positive electrode (anode) when electricity is passed into a solution of an ionic compound.

Question 18.
Electrolytic cell
Answer:
An assembly that consists of a container with an electrolyte and the electrodes dipped in it, is called an electrolytic cell.

Question 19.
Molarity of a solution
Answer:
The number of moles of the solute dissolved in one litre of the solution is called the molarity of that solution. The molarity of a solute is indicated by writing its molecular formula inside a square bracket for example [NaCl] = 1

Question 20.
Acid – base indicators
Answer:
Some natural and synthetic dyes show two different colours in acidic and basic solution, and such dyes are acid base indicators.

Explain the following chemical reactions with the help of balanced equations:

Question 1.
Magnesium reacts with dilute hydrochloric acid.
Answer:
When magnesium reacts with dilute hydrochloric acid, it forms magnesium chloride and hydrogen gas is liberated.

Question 2.
When copper reacts with nitric acid.
Answer:
When copper reacts with nitric acid, it forms copper nitrate and hydrogen gas is liberated.

Question 3.
When ferric oxide reacts with diluted hydrochloric acid.
Answer:
When Ferric oxide reacts with diluted hydrochloric acid, it forms ferric chloride and water.

Question 4.
When calcium oxide reacts with dilute hydrochloric acid.
Answer:
When calcium oxide reacts with dilute hydrochloric acid, it forms calcium chloride and water.

Question 5.
When Magnesium oxide reacts with dilute hydrochloric acid.
Answer:
When magnesium oxide reacts with dilute hydrochloric acid, it forms magnesium chloride and water.

Question 6.
When zinc oxide reacts with dilute hydrochloric acid.
Answer:
When zinc oxide reacts with dilute hydrochloric acid, it forms zinc chloride and water.

Question 7.
When aluminium oxide reacts with hydrogen fluoride
Answer:
When aluminium oxide reacts with hydrogen fluoride, it forms Aluminium fluoride arid water.

Question 8.
When carbon dioxide reacts with sodium hydroxide.
Answer:
When carbon dioxide reacts with Sodium hydroxide, it forms Sodium carbonate and water.

Question 9.
When carbon dioxide reacts with potassium hydroxide.
Answer:
When carbon dioxide reacts with potassium hydroxide, it forms potassium carbonate and water.

Question 10.
When sulphur trioxide reacts with sodium hydroxide.
Answer:
When sulphur trioxide reacts with sodium hydroxide, it forms sodium sulphate and water.

Question 11.
When calcium hydroxide reacts with carbon dioxide.
Answer:
When calcium hydroxide reacts with carbon dioxide, it forms calcium carbonate and water.

Question 12.
When sodium carbonate reacts with hydrochloric acid.
Answer:
When sodium carbonate reacts with hydrochloric acid, it forms sodium chloride, carbon dioxide and water.

Question 13.
When sodium carbonate reacts with sulphuric acid.
Answer:
When sodium carbonate reacts with sulphuric acid, it forms sodium sulphate, carbon dioxide and water.

Question 14.
When calcium carbonate reacts with nitric acid.
Answer:
When calcium carbonate reacts with nitric acid, it forms calcium nitrate, carbon dioxide and water.

Question 15.
When potassium carbonate reacts with sulphuric acid.
Answer:
When potassium carbonate reacts with sulphuric acid, it forms potassium sulphate, carbon dioxide and water.

Question 16.
When sodium bicarbonate reacts with hydrochloric acid. OR Dilute HC1 was poured on baking soda
Answer:
When sodium bicarbonate reacts with hydrochloric acid, it forms sodium chloride, carbon dioxide and water.

Question 17.
When potassium bicarbonate reacts with nitric acid.
Answer:
When potassium bicarbonate reacts with nitric acid, it forms potassium nitrate, carbon dioxide and water.

Question 18.
When sodium bicarbonate reacts with acetic acid.
Answer:
When sodium bicarbonate reacts with acetic acid, it forms sodium acetate, carbon dioxide and water.

Question 19.
When copper sulphate is heated.
Answer:
When copper sulphate is heated it loses it’s water of crystallization to form white anhydrous copper sulphate.

Question 20.
When Ferrous sulphate is heated.
Answer:
When ferrous sulphate is heated it loses its water of crystallization to form white anhydrous ferrous sulphate.

Q.2. (B)-3. Complete the following table.

Question 1.
Complete the following table.
Answer:

Complete the following reactions.

Question 1.
Answer:

Question 2.
Metal + Dilute acid → Salt + Hydrogen
Answer:

Question 3.
Metal oxide + Dilute acid → SaIt + Water
Answer:

Question 4.
Oxide of non-metal + base → salt + water
Answer:

Question 5.
Carbonate salt of metal + dilute acid → Another salt of metal + Carbon dioxide + water
Answer:

Question 6.
Bicarbonate salt of metal + dilute acid → Another salt of metal + carbon dioxide + water
Answer:

Give scientific reasons:

Question 1.
Ionic compound NaCl has very high stability.
Answer:

• The outermost shell of both Na⁺ and Cl^– ions is a complete octet.
• An electronic configuration with a complete octet indicates a stable state.
• A molecule of NaCl has Na⁺ and Cl^– ions. An ionic bond is formed between these ions.
• The force of attraction between them is very strong as it is formed between the oppositely charged Na⁺ and Cl^– ions.
• Therefore NaCl, an ionic compound has very high stability.

Question 2.
Ionic compound dissociates while forming an aqueous solution.
Answer:

• On dissolving in water, an ionic compound forms an aqueous solution.
• In the solid state, the oppositely charged ions in the ionic compound are sitting side by side.
• When an ionic compound being to dissolve in water, the water molecules push themselves in between the ions of the compound and it separates them from each other, that is to say, an ionic compound dissociates while forming an aqueous solution.

Question 3.
Blue coloured copper sulphate crystals become colourless on heating.
Answer:

• Copper sulphate crystals are blue in colour and crystalline in form due to presence of water of crystallisation.
• Each molecule of crystalline copper sulphate contains five molecules of water of crystallisation (CuSO₄.5H₂O).
• On heating, the copper sulphate crystals lose the water of crystallisation and turns into white amorphous powder called as anhydrous copper sulphate.
• Therefore, blue coloured copper sulphate crystals become colourless on heating.

Question 4.
During electrolysis of water, a few drops of sulphuric acid are added to it.
Answer:

• Pure water is a covalent compound and hence it is a non-electrolyte and does not conduct electricity.
• When a few drops of sulphuric acid (H₂SO₄) are added to water.
• Being a strong acid it dissociates almost completely in its solution forming H⁺ cations and \(\mathrm{SO}_{4}^{2-}\) anions.
• The movement of these ions in the solution towards the respective electrodes amount to the conduction of electricity through the solution.
• Therefore, during electrolysis of water, a few drops of sulphuric acid are added to it.

Question 5.
Glucose is a non-electrolyte.
Answer:

• Glucose is a covalent compound
• It does not form any ions in its aqueous solution.
• Due to this aqueous solution of glucose does not conduct electronic current.
• Hence, glucose is a non-electrolyte.

Question 6.
Pure water is a poor conductor of electricity but aqueous solution of sodium chloride conducts electricity.
Answer:

• Pure water does not contain any free ions.
• Sodium chloride (NaCl) is an ionic compound made up of sodium cation (Na⁺) and chloride anion (Cl)
• When sodium chloride is dissolved in water , these ions dissociates in its aqueous solution. ‘
• These ions are free to move in the solution and conduct electricity.
• Therefore, pure water is a poor conductor of electricity but aqueous solution of sodium Chloride conducts electricity.

Question 7.
When carbon dioxide gas is passed through freshly prepared lime water, the limewater turns milky.
Answer:

• Limewater traditionally means a weak solution of the alkali calcium hydroxide Ca(OH)₂.
• When CO₂ is passed through limewater, it reacts with calcium hydroxide to form insoluble particulates (precipitate of calcium carbonate (CaCO₃).
• Calcium carbonate is weak basic salt and this gives a milky white precipitate.
  
• Hence, lime water turns milky when CO₂ gas is passed through it.

Q.3.1. Answer the following:

Question 1.
Write down chemical equations for
(a) Zinc oxide reacts with sodium hydroxide
(b) Aluminium oxide reacts with sodium hydroxide.
Answer:
(a) When zinc oxide reacts with sodium hydroxide, it forms sodium zincate and water

(b) When Aluminium oxide reacts with sodium hydroxide, it forms sodium aluminate and water.

Question 2.
Can we call Al₂O₃ and ZnO acidic oxides on the basis of above reactions.
Answer:

• No, because they also react with acids to form their respective salts and water.
• So, they show the properties of basic oxides also.

Question 3.
Define ‘amphoteric oxides’ and give two examples.
Answer:

• Amphoteric oxides are those oxides which react with both adds as well as bases to form their respective salts and water.
• Amphoteric oxides show the properties of both acidic oxides as well as basic oxides. ZnO and Al₂ O₃ are amphoteric oxides.?

Question 4.
Take a solution of 1g copper sulphate in 50ml water in a 100 ml capacity beaker. Use a thick plate of copper as anode and a carbon rod as cathode. Arrange the apparatus as shown in the figure and pass an electric current through the circuit for some time. Do you see any changes?
Answer:

• A thin film of copper metal is deposited on cathode which is immersed in solution. There is no change in colour of solution
• The electrons from cathode combines with Cu²⁺ ion from the solution forming Cu atoms which were then deposited on the cathode.

Q.3.5. Answer in brief:

Question 1.
What are acids, bases and salts?
Answer:

• Compounds having H⁺ as the basic radical in their molecules are called Acids.
• Compounds having OH^– as the acidic radical in their molecule are called Bases.
• Ionic compounds which have a basic radical other than H⁺ and an acidic radical other than OH^– are called salts.

Question 2.
What is an ionic bond?
Answer:

• The molecule of an ionic compound has two constituents namely cation (positive ion / basic radical) and anion (negative ion / acidic radical).
• There is a force of attraction between these ions as they are oppositely charged, and that is called the ionic bond.
• The force of attraction between one positive charge on a cation and one negative charge on an anion makes one ionic bond.

Question 3.
Give examples to show that proportions of H⁺ and OH^– ions in aqueous solution determines the properties of those solutions.
Answer:
The examples to show that proportions of H⁺ and OH^– ions in aqueous solution determines the properties of those solutions are :

• The proportions of H⁺ and OH ions divides soil into the acidic, neutral and basic, types of soil.
• It is necessary for blood, cell sap etc to have H⁺ and OH^– ions in certain definite proportions for their proper functioning.
• Fermentation carried out with the help of micro-organisms, other biochemical processes and also many chemical processes require the proportion of H⁺ and OH^– ions to be maintained within certain limits.

Question 4.
What is pH scale?
Answer:

1. In 1909, the Danish scientist Sorensen introduced a convenient new scale of expressing H⁺ ion concentration which is found to be useful in chemical and biochemical processes.
2. It is the pH scale (pH: power of hydrogen). The pH scale extends from 0 to 14. According to this scale pure water has a pH of 7. pH 7 indicates a neutral solution. This pH is the midpoint of the scale.
3. The pH of an acidic solution is less than 7 and?

Question 5.
Give the pH of following solutions.
Answer:

Question 6.
What is universal indicator? Which is the most accurate method of measuring the pH of a solution?
Answer:

• In the pH scale, the pH of solutions varies from 0 to 14 in accordance with the strength of the acid or base.
• To show these variations in pH, a universal indicator is used.
• A universal indicator shows different colours at different values of pH. A universal indicator is made by mixing several synthetic indicators in specific proportions.
• The pH of a solution can be determined by means of a universal indicator solution or the pH paper made from it.
• However, the most accurate method of measuring the pH of a solution is to use an electrical instrument called pH meter.
• In this method, pH is measured by dipping electrodes into the solution.

Answer in detail:

Question 1.
Explain the Arrhenius theory of acids and bases.
Answer:
The Swedish scientist Arrhenius put forth a theory of acids and bases in the year 1887. This theory gives definitions of acids and bases as follows:
Acid : An acid is a substance which on dissolving in water gives rise to H ion as the only cation. For example, HCl, H₂SO₄, H₂CO₃

Base: Abase is a substance which on dissolving in water gives rise to the OH ion as the only anion, For example, NaOH, Ca(OH)₂

Question 2.
Write a short note on Neutralization.
Answer:

• Take 10 ml of dilute HCl in a beaker, go on adding dilute NaOH drop by drop and record the pH.
• Stop adding the NaOH when the green colour appears on the pH paper, that is when the pH of solution becomes 7.
• Both HCl and NaOH dissociate in their aqueous solutions.
• Addition of NaOH to HCl solution is like adding a large concentration of OH ions to a large concentration of H⁺ ions.
• However water dissociates into H⁺ and OH ions to a very small extent.
• Therefore on mixing the excess OH^– ions combines with excess H⁺ ions and forms H₂O molecules which mix with solvent water.
• This change can be represented by the ionic equation shown as follows. H⁺ + Cl^– + Na⁺ + OH^– → Na⁺ + Cl^– + H₂O
• It can be observed that Na⁺ and CT ions are there on both the sides. Therefore the net ionic reaction is H⁺ + OH^– → H₂O
• As NaOH solution is added drop by drop to the HCl solution, the concentration of ff goes on decreasing due to combination with added OH ions, and that is how the pH goes on increasing.
• When enough NaOH is added to HCl, the resulting aqueous solution contains only Na⁺ and Cl^– ions, that is, NaCl, a salt, and the solvent water. The only source of H⁺ and OH^– ions in this solution is a dissociation of water.
• Therefore, this reaction is called the Neutralization reaction. The Neutralization reaction is also represented by the following simple equation.
  

Question 3.
Explain the water of Crystallization.
Answer:

• Take some crystals of blue vitriol (CuSO₄. 5H₂O) in a test tube. Heat the test tube on a low flame of a burner.
• It was observed that on heating, the crystalline structure of blue vitriol broke down to form a colourless powder and water came out.
• This water was part of the crystal structure of blue vitriol. It is called water of crystallization.
• On adding water to the white powder a solution
  
  was formed which had the same colour as the solution in the first test tube.
• From this we come to know that no chemical change has occurred in the crystals of blue vitriol due to heating.
• Losing water on heating blue vitriol, breaking down of the crystal structure, losing blue colour and regaining blue colour on adding water are all physical changes.
  
• Similarly, ferrous Sulphate crystals also contain 7 molecules of water of crystallization which are lost on heating.
• The reaction is represented as
  
• Ionic compounds are crystalline in nature. These crystals are formed as a result of definite arrangement of ions.
• In the crystals of some compounds, water molecules are also included in this arrangement.
• That is the water of crystallization. The water of crystallization is present in a definite proportion of the chemical formula of the compound.

Question 4.
Explain the conduction of electricity through solutions of ionic compounds
Answer:

1. Electrons conduct electricity through electrical wires, and ions conduct electricity through a liquid or a solution.
2. Electrons leave the battery at the negative terminal, complete the electric circuit and enter the battery at the positive terminal.
3. When there is a liquid or a solution in the circuit, two rods, wires or plates are immersed in it. These are called electrodes.
4. Electrodes are made of conducting solid. The electrode connected to negative terminal of a battery by means of a conducting wire is called a cathode and the electrode connected to the positive terminal of a battery is called anode.
5. We have seen that salts, strong acids and strong bases dissociates almost completely in their aqueous solutions.
6. Therefore the aqueous solutions of all these three contain large number of cations and anions.
7. A characteristic of liquid state is the mobility of its particles. Due to its mobility the positive charged ions of the solution are attracted to the negative electrode or cathode.
8. On the other hand, the negative charged ions of the solution are attracted to the positive electrode or anode.
9. The movement of ions in the solution towards the respective electrodes accounts to the conduction of electricity through the solution.
10. From this we can understand that those liquids or solutions which contain a large number of dissociated ions conduct electricity.
    

Balbharati Maharashtra State Board 9th Std Science Textbook Solutions

• Laws of Motion Class 9 Science Textbook Solutions
• Work and Energy Class 9 Science Textbook Solutions
• Current Electricity Class 9 Science Textbook Solutions
• Measurement of Matter Class 9 Science Textbook Solutions
• Acids, Bases and Salts Class 9 Science Textbook Solutions
• Classification of Plants Class 9 Science Textbook Solutions
• Energy Flow in an Ecosystem Class 9 Science Textbook Solutions
• Useful and Harmful Microbes Class 9 Science Textbook Solutions
• Environmental Management Class 9 Science Textbook Solutions

Std 9 Science Chapter 14 Substances in Common Use Question Answer Maharashtra Board

Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 14 Substances in Common Use Notes, Textbook Exercise Important Questions and Answers.

Class 9 Science Chapter 14 Substances in Common Use Question Answer Maharashtra Board

Class 9 Science Chapter 14 Substances in Common Use Textbook Questions and Answers

1. Fill in the blanks.

a. The number of molecules of water of crystallization in washing soda is …………….…. .
b. The chemical name of baking soda is …………….…. .
c. …………….…. is used in treatment of hyperthyroidism.
d. The chemical name of Teflon is …………….…. .
Answer:
a. 10
b. Sodium bicarbonate
c. Iodine -123
d. Polytetra fluoroethylene (C₂F₄)_n

2. Match the pairs

Answer:
(1 – c),
(2 – a),
(3 – d),
(4 – b)

3. Write answers to the following

a. What is meant by radioactivity?
Answer:

• Elements with a high atomic number such as uranium, thorium, radium have a property of spontaneously emitting invisible, highly penetrating and high energy radiation.
• This property is called radioactivity.
• A substance having this property is called a radioactive substance.

b. When is said to be the nucleus unstable?
Answer:

• It is the balance of protons and neutrons in a nucleus which determines whether a nucleus will be stable or unstable.
• Too many neutrons or protons upset this balance disrupting the binding energy from the strong nuclear forces making the nucleus unstable.

c. Which diseases are caused by artificial food colours?
Answer:
Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

d. Where in the industrial field is radioactivity used?
Answer:
Industrial field Radiography

• Internal cracks and voids in cast iron articles and iron solder can be detected with the help of gamma rays.
• For this purpose, isotopes like cobalt-60, iridium-192 are used in the radiography camera.
• This technique is used for detecting flaws in metal work.

Measurement of thickness, density and level

• It is necessary to maintain the required thickness in the manufacture of aluminium, plastic, iron sheets of differing thickness.
• In the manufacturing process, a radioactive substance is placed on one side and an instrument to measure radiation on the other.
• The radiation read by the measuring instrument varies with the thickness of the sheet.
• Material inside a packing can also be examined by the same technique.

Luminescent paint and radio luminescence:

• The radioactive substances radium, promethium, tritium with some phosphor are used to make certain objects visible in the dark, for example, the hands of a clock, and certain other objects.
• Krypton-85 is used in HID (High-Intensity Discharge) lamps while promethium – 147 is used in portable X-ray units as the source of beta rays.

Use in Ceramic articles:

• Luminous colours are used to decorate ceramic tiles, utensils, plates, etc.
• Earlier uranium oxide was used in these paints.

e. Write down properties of teflon.
Answer:
Properties of teflon :

• The atmosphere and chemical substances have no effect on Teflon.
• Neither water nor oil will stick to Teflon coated articles.
• High temperatures do not affect Teflon as its melting point is 327 °C.
• Teflon coated articles are easy to clean.

f. What type of colours will you use to celebrate ecofriendly Rang Panchami? Why?
Answer:

• We regularly use artificial colours on Rang Panchami.
• The red colour used on Rang Panchami is very dangerous. It contains a high proportion of mercury in it.
• This poses risks like blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores, etc.
• Therefore, it is necessary to use eco-friendly colours.
• We will prepare colours for Rang Panchami from natural resources such as beet root, flowers of flame of forest, spinach, flame tree (gulmohar) and protect your health by using these.

g. Why has the use of methods like Teflon coating become more common?
Answer:
The use of methods like Teflon coating became more common because of following properties of teflon:

• The atmosphere, rain water and chemical substances have no effect on Teflon.
• Neither water nor oil will stick to Teflon coated articles.
• High temperatures do not affect Teflon as its melting point is 327 °C.
• Teflon coated articles are easy to clean.
• Teflon is a poor conductor of electricity.

4. Give a scientific explanation

a. Bleaching powder has the odour of chlorine.
Answer:

• Bleaching powder undergoes slow decomposition due to the carbon dioxide in air and chlorine gas is released.
• Bleaching powder gets its property because of this release of chorine gas.
  

b. The hard water of a well becomes soft on adding washing soda to it.
Answer:

• The hard water from a well or a bore-well becomes soft on adding washing soda and we come to know this from the lather formed on it.
• The hardness of water is due to the presence of chlorides and sulphates of calcium and magnesium in it.
• Na₂CO₃ is added to it to soften such water and make it suitable for use.
• The reaction with Na₂CO₃ causes the formation of insoluble carbonate salts of magnesium and calcium.
  MgCl_2(aq) + Na₂CO_3(s) → MgCO_3(s) + 2 NaCl_(s)

c. Soap forms a precipitate in hard water.
Answer:

• When soap is mixed with hard water, calcium and magnesium salts of fatty acids are formed.
• These being water insoluble, they form a precipitate and that is why lather is not formed.

d. The particles of powder are given an electric charge while spraying them to form the powder coating.
Answer:

• Powder coating is a method of applying a layer harder than paint on the surface of an iron object to prevent rusting.
• In this method, a polymer resin, a pigment and some other ingredients are melt, mixed, cooled and ground into a uniform powder.
• This powder is sprayed on the polished metal surface by electrostatic spray deposition (ESD).
• In this method, the particles of the powder are given an electrostatic charge due to which a uniform layer of the powder sticks to the metal surface.
• Then the object is heated in the oven along with the coating.
• A chemical reaction occurs in the layer, resulting in the formation of long cross-linked polymeric chains.

e. The aluminium article is used as an anode in the anodising process.
Answer:

• A protective layer is formed naturally on the surface of aluminium metal by reaction with oxygen in air.
• In the anodizing process, this layer is made of the desired thickness. Anodizing is done by electrolysis.
• Dilute Sulphuric acid is taken in the electrolytic cell and the aluminium article is dipped in it as the anode.
• When an electric current is passed, hydrogen gas is released at the cathode and oxygen gas at the anode.
• A reaction with oxygen occurs and a layer of hydrated aluminium oxide is formed on the anode. Therefore, aluminium article is used as an anode in the anodizing process.

f. When the radiation coming out from certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path.
Answer:
(i) When the radiation coming out from certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path. This is because the radiation coming out from radioactive substance are of three types Alpha rays, Beta rays and Gamma rays.

(ii) The rays which get deviated slightly towards negatively charged plate are called alpha rays. They get deviated towards negatively charged plate because they are made of positively charged particles, called as alpha particles (He++).

(iii) The rays which get deviated substantially towards the positively charged plate are called beta rays. They get deviated towards a positively charged plate because they are made of negatively charged particles called as beta particles (e-).

(iv) The rays which do not deviate at all are called gamma rays. They are uncharged electromagnetic radiation. Hence, marks are found at three places on the photographic plate. (For diagram refer Fig. 14 .2 from Q. 4(3))

g. A certain type of ceramic tiles are fixed on the outer layer of a space shuttle.
Answer:
(i) Each shuttle is covered by more than 24,000 of the six- by six-inch advance ceramic tiles. This tiles withstand high temperatures without decomposing. They are brittle, water-resistant and electrical insulator. Most of the tiles are made of silica fibres, which are produced from high-grade sand (SiO₂).

(ii) Silica is an excellent insulator because it transports heat slowly. When the outer portion of a tile gets hot, the heat takes a long time to work its way down through the rest of the tile to the shuttle’s skin. The tiles keep the orbiter’s aluminium skin at 350 degrees or less.

(iii) The silica fibers are mixed with water and chemicals, and the mixture is poured into molds, which are zapped in microwave ovens at 2,350°C to fuse the silica fibres. Tiles are too brittle to attach to the orbiter directly.

(iv) The shuttle’s skin contracts slightly while in orbit, then expands during re-entry.

(v) In addition, the stresses of launch and re-entry cause the skin to flex and bend. Such motions could easily crack the tiles or shake them off. To keep them in place, workers glue the tiles to flexible felt-like pads, then glue the pads to the orbiter.

5. Write answers to the following

a. Write about artificial food colours, the substances used in them and their harmful effects.
Answer:
(a) Artificial food colour and substances in them.

• Food colours are mixed in most soft drinks and foodstuffs available in the market.
• These food colours are in the form of powders, gels and pastes.
• Food colours are used in domestic as well as commercial products.
• Certain colours and essences are added to ice cream, ice candies, sauce, fruit juices, cold drinks, pickles, jams and jelly.
• Food colours are often found to be added to packaged meat (chicken, mutton), chilli powder, turmeric, sweets and other similar substances so as to give them a good colour.
• Tetrazene, sunset yellow are artificial food colours used extensively.

(b) Harmful effects of artificial food colours

1. Food colours added to pickles, jam and sauce contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis.
2. Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

b. What is meant by water of crystallization? Give examples of salts with water of crystallization, and their uses.
Answer:
The exact number of water molecules which are chemically bonded to a molecule of a salt within a hydrated crystalline compound is called as water of crystallization are:

Some substances in our daily use which contain water of crystallization are:

• Alum (Potash alum – K₂SO₄.Al₂(SO₄)₃.24H₂O)
• Borax (Na₂B₄O₇.10H₂O)
• Epsom salt (Magnesium sulphate MgSO₄.7H₂O)
• Barium chloride (BaCl₂.2H₂O)
• Sodium sulphate (Glauber’s salt Na₂SO₄.10 H₂O)
• Blue vitriol (Copper Sulphate – CuSO₄.5H₂O)

Uses of these salts are as given below:
(i) Alum (Potash alum – K₂SO₄.Al₂(SO₄)₃.24H₂O)

• Alum is used in the process of water purification.
• Because of the property of coagulation, the solid impurities in water come together, become heavy and settle to the bottom. As a result, the impure water or muddy above becomes clear.
• Alum powder, found in the spice section of many grocery stores, may be used in pickling recipes as a preservative to maintain fruit and vegetable crispness.
• Alum is used as the acidic component of some commercial baking powders.
• Alum has been used as an after shave treatment.

(ii) Borax (Na₂B₄O₇.10H₂O)

• Borax today is used for many cleaning purposes.
• It is used to make homemade laundry detergent.
• It is added as a cleaning boost to any other detergent.
• It even keeps ants and other pests away.

(iii) Epsom salt (Magnesium sulphate MgSO₄.7H₂O)

• Epsom salt is used as a relaxing magnesium bath soak.
• To grow better vegetables – Add a tablespoon of Epsom salt to the soil below a vegetable plant to boost growth.

(iv) Barium chloride (BaCl₂.2H₂O)

• In industry, Barium chloride is mainly used in the purification of brine solution in caustic chlorine plants.
• It is also used in the manufacture of heat treatment salts.
• It is used in hardening of steel.
• It is used in the manufacture of pigments.

(v) Sodium sulphate (Glauber’s salt Na₂SO₄.10H₂O)

• In the laboratory, anhydrous Sodium sulphate is widely used as an inert drying agent, for removing traces of water from organic solutions.
• Glauber’s salt, the decahydrate, is used as a laxative.

(vi) Blue vitriol (Copper sulphate CuSO₄.5H₂O)

• Blue vitriol is used in the blood test for diagnosing anaemia.
• Slaked Time is used with blue vitriol in the Bordeaux mixture which is used as a fungicide on fruits like grapes and musk melon.

c. Write briefly about the three methods of electrolysis of sodium chloride.
Answer:

• When an electric current is passed through a saturated solution of sodium chloride (brine) it is electrolysed and hydrogen gas is released at the cathode while chlorine gas is released at the anode.
• This method is used for production of chlorine gas. In this method an important basic compound NaOH is formed in the cell.
• Chemical reaction
  2NaCl + 2H₂O → 2NaOH + Cl₂ ↑ + H₂↑
• When salt is heated to a high temperature (about 800 °C), it melts. This is called the fused state of the salt.

6. Write the uses.

a. Anodizing
b. Powder coating
c. Radioactive substances
d. Ceramic
Answer:
(a) Anodizing : Anodizing is done on aluminum cooking utensils like griddles and cookers.

(b) Powder coating : Powder coating is done on iron objects to prevent rusting. Also, on Plastic and Medium density fibre (MDF) board, to make them highly durable, hard and attractive.

(c) Radioactive substances:
(I) Industrial field:
(i) Industrial Radiography : Internal cracks and voids in cast iron articles and iron solder can be. detected with the help of gamma rays. For this purpose, isotopes like cobalt-60, iridium-192 are used in the radiography camera. This technique is used for detecting flaws in metal work.

(ii) Measurement of thickness, density and level: It is necessary to maintain the required thickness in the manufacture of aluminium, plastic, iron sheets of differing thickness. In the manufacturing process, a radioactive substance is placed on one side and an instrument to measure radiation on the other. The radiation read by the measuring instrument varies with the thickness of the sheet. Material inside a packing can also be examined by the same technique.

(iii) Luminescent paint and radioluminescence:
The radioactive substances radium, promethium, tritium with some phosphor are used to make certain objects visible in the dark, for example, the hands of a clock, and certain other objects. Krypton-85 is used in HID (High Intensity Discharge) lamps while promethium-147 is used in portable X-ray units as the source of beta rays.

Use in Ceramic articles – Luminous colours are used to decorate ceramic tiles, utensils, plates, etc. Earlier uranium oxide was used in these paints.

(II) Field of agriculture :

• The genes and chromosomes that give seeds properties like fast growth, higher productivity, etc. can be modified by means of radiation.
• The radioactive isotope cobalt-60 is used for food preservation.
• Onions, potatoes are irradiated with gamma rays from cobalt-60 to prevent their sprouting.
• Strontium-90 is used as a tracer in the research on various crops.

(III) Medical science:

• Polycythemia : The red blood cell count increases in the disease polycythemia. Phosphorus- 32 is used in its treatment.
• Bone cancer : Strontium-89, strontium-90, samarium-153 and radium-223 are used in the treatment of bone cancer.
• Hyperthyroidism : Enlargement of thyroid gland, weight loss in spite of appetite, insomnia are the symptoms of hyperthyroidism.
• It occurs due to overproduction of hormones by the thyroid gland. Iodine-123 is used in the treatment of hyperthyroidism.
• Tumour detection : Boron-10, iodine-131, cobalt-60 are used in treatment of brain tumour, while arsenic-74 is used in detection of small tumours in the body.

(d) Ceramic : Pots made by a potter, Mangalore roofing tiles, construction bricks, pottery, terracotta articles are some examples of common ceramic articles that we see around.

7. Write the harmful effects

a. Artificial dye
b. Artificial food colour
c. Radioactive substances
d. Deodorant
Answer:
(a) Artificial dye:

• Dyeing hair can have adverse effects like hair fall, damage to hair texture, burning of skin, adverse effect on eyes, etc.
• Lipstick contains a dye named carmine. It does not affect lips but causes stomach disorders.
• Excessive use of plants for making natural dyes results in deterioration of the environment.

(b) Artificial food colour:

• Food colours added to pickles, jams and sauces contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis.
• Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

(c) Radioactive substances :

• The central nervous system is affected by radioactive radiations.
• Hereditary defects are generated by bombardment of radiation on D.N.A in the body.
• Radioactive radiation can penetrate the skin, and causes diseases like skin cancer, leukemia.
• The radioactive pollutants created due to explosions enter the body through air and it is difficult to control them.
• The radioactive pollutants released in the sea enter the bodies of fishes and through them enter the human body.
• The radioactive paint on the watch can cause cancer.
• The radioactive isotopes strontium-90 can enter the body through plants, fruits, flowers, cereals, milk, etc. and cause diseases like bone cancer, leukemia.

(d) Deodorant:

• Aluminium – Zirconium compounds are the most harmful chemicals in the deodorant. Disorders like headache, asthma, respiratory disorders, heart disease are likely to occur without our knowledge.
• There is a possibility of various skin disorders and also skin cancer due to the aluminium chlorohydrates.

8. Write the chemical formula Bleaching powder, common salt, baking soda, washing soda
Answer:

9. Explain what you see in the following picture

Powder coating
Answer:

1. This picture shows powder coating of the given object. Powder coating is a method of applying a layer harder than paint on the surface of an iron object to prevent rusting.
2. In this method, a polymer resin, a pigment and some other ingredients are melt mixed, cooled and ground into a uniform powder.
3. This powder is sprayed on the polished metal surface by electrostatic spray deposition (ESD).
4. In this method, the particles of the powder are given an electrostatic charge due to which a uniform layer of the powder sticks to the metal surface.
5. Then the object is heated in the oven along with the coating.
6. A chemical reaction occurs in the layer, resulting in the formation of long cross-linked polymeric chains.
7. This powder coating is highly durable, hard and attractive. Powder coating can be done on plastic and medium density fibre (MDF) board in day to day use as well.

Class 9 Science Chapter 14 Substances in Common Use Intext Questions and Answers

Can you recall?

Question 1.
What are detergents?
Answer:

• Detergent is a water-soluble cleansing agent which combines with impurities and dirt to make them more soluble, and differs from soap in not forming a scum with the salts in hard water.
• Today, detergents are more likely to be a mixture of synthetic chemicals and additives cooked up in a huge chemical plant and, unlike traditional soap, they’re generally liquids rather than solids.
• Detergents are used in everything from hair shampoo and clothes, washing powder to shaving foam and stain removers.
• The most important ingredients in detergents are chemicals called surfactants – a word made from bits of the words surface-active agents.

Question 2.
What are the important substances that we use in day to day life? For what purposes do we use them?
Answer:
Some of the substances we use in our day to day life and the purpose of using them are as follows:

Toothpaste: for cleaning teeth and maintaining hygienic conditions of mouth.

Soap : for bathing and maintaining hygienic conditions of body.

Natural and artificial fibers : we wear them as clothes to protect our body and many other purposes.

Washing powder: for cleaning clothes. Vegetables, fruits and food grains : they provide us with necessary vitamins, minerals and carbohydrates required for proper functioning of body.

Water : very important for our survival and many other functions of day to day life.

Metals : for making buildings, bridges, roads, vehicles, trains, ships, airplanes, utensils etc.

Acids, bases and salts : used for various purposes, for example, Sodium chloride which is used as common salt, a very necessary ingredient of our daily food without which our food is tasteless.

Question 3.
How are the various substances in day to day use classified from the scientific point of view?
Answer:
The various substances in day to day use are classified from the scientific point of view as elements, compounds, mixtures, metals, non-metals, acids, bases and salts.

Question 4.
Which chemicals and apparatus will you use in the laboratory for making soap?
Answer:
For making soap in laboratory following chemicals and apparatus are used :
Chemicals : Vegetable oil (coconut oil, castor oil, soya bean oil etc.)
Sodium hydroxide (NaOH)
Salt (Sodium chloride NaCl)

Apparatus :
500 ml glass beaker
Burner
Flat glass tray
Knife

Soaps are essential to personal and public health. They safely remove germs, soils and other contaminants and help us to stay healthy and make our surroundings more pleasant. Soaps are made from fats and oils or their fatty acids.

Take about 20 ml of any vegetable oil (coconut oil, castor oil, soybean oil etc.) in a beaker. Put about 30 – 35 ml of NaOH in it and heat and stir the mixture till a paste is formed. Now add a little salt. Stir again and allow the mixture to cool in a flat glass tray, on cooling it solidifies. Take a knife and cut it in soap bars as per the size required.

Question 5.
What are salts?
Answer:

• Inorganic substances occur naturally in the form of salts rather than acids or bases.
• The ionic compounds which do not contain H+ and OH ions and contain only one kind of cation and anion are called simple salts.
• For example, Na₂SO₄, K₃PO₄, CaCl₂.
• The sea is said to be a rich source of salts. In fact, the sea is a rich source of several salts of various elements such as chlorine, sodium, magnesium, potassium, calcium, bromine.
• The important salts found in sea water are sodium chloride, magnesium chloride, magnesium sulphate, potassium chloride, calcium carbonate and magnesium bromide.

Answer the following questions:

Question 1.
How is it determined whether a substance is acidic, basic or neutral?
Answer:

• In the pH scale, the pH of solutions varies from 0 to 14 in accordance with the strength of the acids or base.
• The pH scale shows different colours at different values of pH. Colour from dark red to yellow or from pH value 0 to 6 indicates the substances are acidic.
• Colour from light blue to violet or from pH value 8 to 14 indicates the substances are basic.
• Green colour or pH value 7 indicates the substances are neutral.

Question 2.
A sweets shop looks attractive because of the colourful sweets displayed there. Which colours are used in these substances?
Answer:

• Food colours and essences are used in sweets to make them colourful and tasty.
• These food colour are in the form of powders, gels and pastes.
• Food colours are natural as well as artificial.
• The food colours prepared from seeds, beetroot, flowers and fruit concentrate are natural.
• Tetrazene, sunset yellow are artificial food colours used extensively.

Question 3.
Make a list of substances in day to day use in accordance with their pH value (O to 14).
Answer:

Question 4.
A doctor gives you medicines when you fall ill. What are the medicines made from?
Answer:

• Long before pure chemicals were manufactured in labs, people used plants for medicine.
• There are over a hundred active ingredients derived from plants for use as drugs and medicines.
• The emergence of synthetic chemistry in the 1800s opened up new avenues for scientific research into drugs.
• Many chemists tried to locate medically active ingredients in plants (for instance the important malaria remedy quinine), and subsequently tried to make those substances in the laboratory in order to become independent of plant supplies.
• At the same time, a new industry developed as scientists developed processes to synthesise new chemicals on a large scale.
• New production methods developed in the late 1800s and early 1900s made it easier to standardise, package and transport medicines.

Question 5.
What problems do you get after playing colours on Rang Panchami? Why?
Answer:

• After playing colours on Rang Panchami we may get problems such as risks of blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores etc.
• This is because the colours used in rang panchami specially the red colour is very dangerous.
• It contains a high proportion of mercury in it.

Question 6.
Which colours will you use to prevent the occurrence of these problems?
Answer:

• To prevent the occurrence of these problem, instead of using artificial colours, natural colours should be used.
• Natural colours are prepared from natural resouroes such as beet root, flowers of flame of forest, spinach, flame tree (gulmohar).

Question 7.
What problem do you have on painting the house and furniture?
Answer:

• On painting the house and furniture with artificial colours which are dangerous, we may get problems such as risks of blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores, etc.
• This is because the colours contain a high proportion of mercury in it.

Question 8.
What is the property of Teflon because of which it is used in non-stickware?
Answer:
Following are the properties of teflon because of which it is used in nonstick cookware.

• The atmosphere and chemical substances have no effect on Teflon.
• Neither water nor oil will stick to Teflon coated non-stickware.
• High temperatures do not affect Teflon as its melting point is 327 °C.
• Teflon coated non-stickware are easy to clean.

Answer the following questions:

Question 1.
What is the strip shown below? What is it used for?
Answer:
The strip shown is pH metre scale. It is used to determined pH of solutions.

Question 2.
Prepare saturated solutions of given salts and put 2-3 drops of the universal indicator in them and note your observations in the table below:
Answer:

Class 9 Science Chapter 14 Substances in Common Use Additional Important Questions and Answers

Select the correct option:

Question 1.
Baking soda is ………………………… .
(a) non-metallic
(b) metallic
(c) acidic
(d) basic
Answer:
(d) basic

Question 2.
During electrolysis of NaCl in the fused state ………………………… is formed at cathode.
(a) sodium
(b) oxygen
(c) oxalic acid
(d) butyric acid
Answer:
(a) sodium

Question 3.
………………………… is known as chloride of lime.
(a) Calcium carbonate
(b) Sodium bicarbonate
(c) Sodium chloride
(d) Bleaching powder
Answer:
(d) Bleaching powder

Question 4.
Salt obtained from certain type of rock is called ………………………… .
(a) hard salt
(b) rock salt
(c) stone salt
(d) pure salt
Answer:
(b) rock salt

Question 5.
The ………………………… % aqueous solution of salt is called brine.
(a) 25
(b) 60
(c) 30
(d) 50
Answer:
(a) 25

Question 6.
The molecular formula for baking soda is ………………………… .
(a) Na₂CO₃
(b) NaHCO₃
(c) Na₂SO₄
(d) NaNO₃
Answer:
(b) NaHCO₃

Question 7.
Bleaching powder is also called ………………………… .
(a) Calcium oxygen chlorine
(b) Calcium oxychloride
(c) Calcium hydroxide
(d) Calcium oxalate
Answer:
(b) Calcium oxychloride

Question 8.
NaHCO₃ is also called as ………………………… .
(a) Sodium carbonate
(b) Sodium bicarbonate
(c) Sodium carbon oxide
(d) Sodium chloride
Answer:
(b) sodium bicarbonate

Question 9.
Molecular formula for Magnesium bromide is ………………………… .
(a) MgBr
(b) Mg₂Br
(c) Mg₂Br₂
(d) MgBr₂
Answer:
(d) MgBr₂

Question 10.
The molten state of NaCl is also called as ………………………… .
(a) solid state
(b) semi-solid
(c) gaseous state
(d) fused state
Answer:
(d) fused state

Question 11.
Substance used to make hard water soft is ………………………… .
(a) Na₂CO₃.10H₂O
(b) Na₂CO₃.H₂O
(c) NaCO₃.10H₂O
(d) NaCO₃.H₂O
Answer:
(a) Na₂CO₃.10H₂O

Question 12.
The fixed number of molecules of water in alum is ………………………… .
(a) 24
(b) 10
(c) 7
(d) 2
Answer:
(a) 24

Question 13.
Chlorine gas is a strong ………………………… agent.
(a) reducing
(b) oxidising
(c) neutral
(d) acidic
Answer:
(b) oxidising

Question 14.
Bleaching powder is ………………………… in colour.
(a) brownish red
(b) yellowish-white
(c) pinkish brown
(d) greenish blue
Answer:
(b) yellowish-white

Question 15.
Soap is ………………………… in nature.
(a) acidic
(b) basic
(c) neutral
(d) fuming
Answer:
(b) basic

Question 16.
Melting point of NaCl is ………………………… .
(a) 400°C
(b) 100°C
(c) 800°C
(d) 600°C
Answer:
(c) 800°C

Question 17.
Rock salt is ………………………… in colour.
(a) black
(b) white
(c) brown
(d) blue
Answer:
(c) brown

Question 18.
Strong odour in swimming pool is due to ………………………… .
(a) chlorine gas
(b) impurities
(c) calcium carbonate
(d) calcium hydroxide
Answer:
(a) chlorine gas

Question 19.
Molecular formula of sodium bicarbonate is ………………………… .
(a) NaHCO₃
(b) Na₂HCO₃
(c) Na₂HCO₂
(d) NaHCO₂
Answer:
(a) NaHCO₃

Question 20.
Soap is ………………………… in nature.
(a) radioactive
(b) natural
(c) acidic
(d) basic
Answer:
(d) basic

Question 21.
The molecular formula for Magnesium bromide is ………………………… .
(а) MgBr
(b) MgBr₂
(c) Mg₂Br₂
(d) Mg₂Br
Answer:
(b) MgBr₂

Fill in the blanks and rewrite the complete statements:

(1) 25% of NaCl is known as
(2) gas is released when bleaching powder is added to water.
(3) Washing soda is as it absorbs moisture if left exposed to air.
(4) is used to make hard water soft.
(5) Molecular formula for Alum is
(6) is used in blood test for diagnosing anaemia.
(7) High grade of and are used as raw material to manufacture bathing soap.
(8) Pickles, jams and sauce contain small quantities of and
(9) Excessive consumption of foods with added food colours leads to diseases like
(10) Melting point of Teflon is
(11) Anodizing is done by
(12) The red blood cell count increases in the disease
(13) Magnesium sulphate (MgS04.7H20) is also called
Answer:
(1) Brine
(2) Chlorine
(3) hygroscopic
(4) Na₂CO₃ (Washing soda)
(5) K₂SO₄.Al₂(SO)₃.24H₂O
(6) Blue Vitriol
(7) fats, oils
(8) lead, mercury
(9) ADHD (Attention Deficit Hyperactivity Disorder)
(10) 327°C
(11) Electrolysis
(12) Polycythemia
(13) Epsom salt
(14) Soap

State whether the following statements are true or false. Correct the false statements.
(1) Bleaching powder is used in preparation of chloroform which is used as an anaesthetic.
(2) On addition of universal indicator the colour of table salt changes to pink.
(3) Borax is Na₂B₄O₇.9H₂O.
(4) Boron -10 is used to cure bone cancer.
(5) Clinical deo contains 20 to 25% of aluminium.
(6) NaHCO₃ is sodium carbonate.
(7) Soap is acidic in nature.
(8) Baking powder is neutral in nature.
(9) POP is crystalline in nature.
(10) pH value of universal indicator is 0 – 7.
(11) Sodium chloride is formed by neutralization reaction between sodium hydroxide and calcium carbonate.
(12) Boiling point of NaCl is 800 °C.
(13) Molten state of NaCl is also called as solid state.
(14) Mineral halite is an example of Rock Salt.
(15) Sodium bicarbonate is used to reduce acidity.
(16) Bleaching powder is also called as chloride of lime.
(17) Bleaching powder is obtained by reaction of chlorine gas with slaked lime.
(18) Bleaching powder available in market is classified on the basis of colour.
(19) The hard water becomes soft on adding baking soda (NaHCO₃)
Answer:
(1) True
(2) False. On addition of universal indicator the colour of table salt changes to green.
(3) False. Borax is Na₂B₄O₇.9H₂O
(4) False. Boron – 10 is used in treatment of brain tumour.
(5) True
(6) False. NaHCO₃ is sodium bicarbonate.
(7) False. Soap is basic in nature.
(8) False. Baking powder is basic in nature.
(9) False. POP is amorphous in nature.
(10) False. pH value of universal indicator is 0 -14.
(11) False. Sodium chloride is formed by a neutralization reaction between sodium hydroxide and hydrochloric acid.
(12) False. Melting point of NaCl is 800°C.
(13) False. Molten state of NaCl is also called as fused state.
(14) True
(15) True
(16) True
(17) True
(18) False. Bleaching powder available in market is classified on the basis of percentage of chlorine present in it.
(19) False. Hard water becomes soft on adding washing soda (Na₂CO₃.10H₂O)

Name the following:

Question 1.
Important salts found in sea water.
Answer:
Magnesium chloride, Potassium chloride

Question 2.
Chemical used in preparation of breads and cakes to make them soft.
Answer:
Sodium bicarbonate

Question 3.
Gas liberated when bleaching powder is added to CO₂ gas.
Answer:
Chlorine (Cl₂) gas.

Question 4.
Salt used in refining petroleum
Answer:
Sodium carbonate (Na₂CO₃)

Question 5.
Chemical formula of bleaching powder
Answer:
CaOCl₂

Question 6.
The chemical formula of Sodium hydrogen carbonate.
Answer:
NaHCO₃

Question 7.
Nature of soap.
Answer:
Basic

Question 8.
Molecular formula for Magnesium bromide
Answer:
MgBr₂

Question 9.
Melting point of NaCl
Answer:
800 °C

Question 10.
Two examples of Rock Salt
Answer:
Mineral halite and Himalayan rock salt.

Question 11.
Uses of sodium bicarbonate
Answer:
To prepare breads, cakes and dhokla

Question 12.
Constituents of baking powder.
Answer:
Baking soda and mild acid (tartaric acid)

Question 13.
Substance used to make hard water soft.
Answer:
Washing soda i.e. Na₂CO₃.10H₂O.

Question 14.
Radioactive isotopes used in treatment of bone cancer.
Answer:
Strontium – 89, Strontium – 90, Samarium -153, Radium – 223

Question 15.
Use of Strontium 89 and strontium 90.
Answer:
Treatment of bone cancer.

Select the odd man out:

Question 1.
Sodium sulphate, Barium chloride, Magnesium sulphate, Bleaching powder.
Answer:
Bleaching powder, all others are crystalline salt with water of crystallization while bleaching powder is not.

Question 2.
Strontium – 89, Strontium – 90, Radium – 223, Iodine -123.
Answer:
Iodine -123, it is used to cure hyperthyroidism while others are used to cure bone cancer.

Question 3.
Soap, Toothpaste, Baking soda, Curd.
Answer:
Curd, it is acidic in nature while others are basic in nature.

Question 4.
Na₂CO₃.10H₂O, Na₂SO₄.10H₂O, BaCl₂.2H₂O, CaOCl₂
Answer:
CaOCl₂, it is amorphous in nature while rest are crystalline in nature.

Question 5.
Boron-10, Iodine – 131, Cobalt – 60, Iodine – 123.
Answer:
Iodine -123, it is used in hyperthyroidism while rest are used in treatment of brain tumour.

Question 6.
Na₂SO₄, K₃PO₄, MgBr₂, HCl.
Answer:
HCl, rest all are salts but HCl is an acid.

Write the correlated terms:

(1) Washing Powder : Basic :: Milk : ……………………………
(2) Na₂SO₄: Sodium sulphate :: K₃PO₄ : ……………………………
(3) CaOCl₂: Calcium Oxychloride : : NaHCO₃ : ……………………………
(4) Borax : 10H₂O : : Alum : ……………………………
(5) Sodium Sulphate : Na₂SO₄.10H₂O : : Magnesium Sulphate : ……………………………
(6) Bathing soap : High grades fats and oils :: Washing soap : ……………………………
(7) Radium – 23 : Bone cancer :: Phosphorus – 32 : ……………………………
(8) Iodine -123 : Hyperthyroidism :: Iodine -131 : ……………………………
(9) Clinical deo : 20-25% of aluminium : : Antiperspirant deo : of aluminium chlorohydrate : ……………………………
(10) Sodium carbonate : Na₂CO₃ : : Sodium bicarbonate : ……………………………
(11) Curd : Acidic : : Soap : ……………………………
(12) Calcium Carbonate : CaCO₃ : : Magnesium bromide : ……………………………
(13) Baking Soda : NaHCO₃ : : Washing Soda : ……………………………
(14) Baking Soda : Breads and Cakes : : Washing Soda : ……………………………
(15) Borax : Na₂B₄O₇.10H₂O : : Alum : ……………………………
Answer:
(1) Acidic
(2) Potassium phosphate
(3) Sodium hydrogen carbonate
(4) 24H₂O
(5) MgSO₄.7H₂O
(6) Low-grade fats and oils
(7) Polycythemia
(8) Tumour detection
(9) 15%
(10) NaHCO.
(11) Basic
(12) MgBr₂
(13) Na2CO₃.10H₂O
(14) Hard water soft
(15) K₂SO₄.Al₂(SO₄)₃.24H₂O

Match the columns:

Question 1.

Answer:
(1 – c),
(2 – d),
(3 – b),
(4 – a)

Question 2.

Answer:
(1 – d),
(2 – a),
(3 – b),
(4 -c)

Give scientific reasons:

Question 1.
Baking soda is used while making cakes.
Answer:

• Baking soda is chemically known as sodium bicarbonate.
• On heating, sodium bicarbonate decomposes to form sodium carbonate, water and carbon dioxide (CO,).
• The carbon dioxide produced is released due to which the cake becomes soft and spongy.
• Hence, baking soda is used to make cake spongy and soft.

Question 2.
Baking soda is used to reduce acidity in the stomach.
Answer:

• Baking soda is used as a medicine (antacid). When it is taken, it undergoes hydrolysis to give sodium hydroxide in the stomach. Thus, sodium hydroxide neutralizes the hydrochloric acid produced by gastric juice and gives relief to the patient from acidity.
  

Question 3.
Tap water and water in swimming pool has a typical strong odour in the rainy season.
Answer:

• Tap water and water in swimming pool has a typical strong odour in the rainy season, it is the odour of the chlorine gas that is used to destroy the microbes in the water.
• Chlorine gas is a strong oxidizing agent and therefore, it has a strong disinfecting as well as bleaching action.
• Chlorine is inconvenient to handle because of its gaseous state. Instead, the solid bleaching powder which has the same effect is more convenient to use.
• Bleaching powder undergoes slow decomposition due to the carbon dioxide in air and chlorine gas is released. Bleaching powder gets its property because of this release of chlorine gas.
  

Question 4.
Sodium carbonate is added to hard water to make it soft.
Answer:

• The hardness of water is due to the presence of chlorides and sulphates of calcium and magnesium in it.
• Na₂CO₃ is added to it to soften such water and make it suitable for use.
• The reaction with Na₂CO₃ causes the formation of insoluble carbonate salts of magnesium and calcium thus making the water soft.
  

Question 5.
Alum is used in the process of water purification.
Answer:

• Alum is used in the process of water purification because of property of coagulation.
• The solid impurities in water come together, become heavy and settle to the bottom.
• As a result, the water above becomes clear.

Question 6.
Overconsumption of artificial food colours should be avoided?
Answer:

• The overconsumption of artificial food colours should be avoided because they can be detrimental to health.
• Food colours added to pickles, jam and sauce contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis.
• Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

Question 7.
Artificial colours in Rang Panchami should be used cautiously.
Answer:

• We regularly use artificial colours on Rang Panchami.
• The red colour used on Rang Panchami is very dangerous. It contains a high proportion of mercury in it.
• This poses risks like blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores etc.
• Therefore, it is necessary that artificial colours are used cautiously.

Question 8.
There are various brands of bleaching powder in the market.
Answer:

• When bleaching powder comes in contact with air, it reacts with carbon dioxide to form calcium carbonate and releases chlorine gas. CaOCl₂ + CO₂ → CaCO₃ + Cl₂ ↑ (from air)
• This generated chlorine is known as “available chlorine.”
• On the basis of the percentage of “available chlorine” various brands of bleaching powder are available in the market.

Question 9.
We use anodized cooking utensils like griddles and cookers.
Answer:

• Anodizing is process of forming a protective rayer of hydrated aluminium oxide on utensils.
• Due to anodizing, the surface of the cooking utensils become non-standing, non-toxic and non-reactive with the ingredients of the foot.
• These utensils get heated faster and withstand high heat.
• Also the amount of butter, ghee or oil used to cook food in these type of utensils is neglible.
• These utensils are tough, durable and resistant to corrosion.
• Hence, we use anodized cooking utensils like gridders and cookers.

Explain the following chemical reactions with the help of balanced equations :

Question 1.
Sodium hydroxide reacts with dilute Hydrochloric acid.
Answer:
When Sodium hydroxide reacts with dilute Hydrochloric acid, it forms sodium chloride and water.
This is a neutralization reaction.

Question 2.
When an electric current is passed through a saturated solution of sodium chloride (brine)
Answer:
When an electric current is passed through a saturated solution of sodium chloride (brine) it is electrolysed and hydrogen gas is released at the cathode while chlorine gas is released at the anode. Also, an important basic compound NaOH is formed in the cell.

Question 3.
Baking soda (Sodium hydrogen carbonate) reacts with dilute hydrochloric acid.
Answer:
When Sodium bicarbonate (Sodium hydrogen carbonate) reacts with dilute hydrochloric acid, it gives sodium chloride, water and carbon dioxide gas is liberated.

Question 4.
Bleaching powder is exposed to air.
Answer:
When bleaching powder is exposed to air, it undergoes slow decomposition due to the carbon dioxide in air and chlorine gas is released.

Question 5.
When dry slaked lime reacts with chlorine gas.
Answer:
When dry slaked lime reacts with chlorine gas, it gives bleaching powder.

Question 6.
Bleaching powder reacts with dilute sulphuric acid.
Answer:
Dilute sulphuric acid reacts rapidly with bleaching powder to form calcium sulphate and release chlorine gas completely.

Question 7.
Bleaching powder reacts with dilute hydrochloric acid.
Answer:
Dilute hydrochloric acid reacts rapidly with bleaching powder to form Calcium chloride and release chlorine gas completely.

Question 8.
Sodium carbonate reacts with magnesium chloride.
Answer:
When Sodium carbonate reacts with magnesium chloride, it forms insoluble magnesium carbonate and sodium chloride. This reaction is used to make hard water soft.

Question 9.
Crystalline sodium carbonate is exposed to air.
Answer:
When crystalline sodium carbonate is exposed to air it loses its water of crystallization readily and a white powder is obtained. This powder is called washing soda.

Question 10.
Sodium carbonate reacts with sulphuric acid.
Answer:
When sodium carbonate reacts with sulphuric acid it forms sodium sulphate, water and carbon dioxide gas is liberated.

Distinguish between;

Question 1.
Washing soda and Baking soda
Answer:

Question 2.
Bathing soap and Washing soap
Answer:

Answer the following:

Question 1.
Give the properties and uses of Sodium bicarbonate.
Answer:
Properties and uses of sodium bicarbonate

• (i) NaHCO₂ reacts with moist litmus paper and red litmus turns blue which means that it is basic in nature.
• (ii) It is used to make bread, cake, dhokla.
• (iii) Being basic in nature it is used to reduce acidity in the stomach.
• (iv) NaHCO₃ is used to make the active substance CO₂ in the fire extinguisher.
• (v) Baking soda is used to clean an oven.

Question 2.
Give the properties and uses of washing soda.
Answer:
Properties and uses of washing soda :

• Washing soda is a whitish and odourless powder at room temperature.
• Litmus has a blue colour in its aqueous solution.
• It is hygroscopic, that is, it absorbs moisture if left exposed to air.
• It is used mainly for washing clothes.
• Sodium carbonate is used in the glass and paper industry and also in refining of petrol.

Question 3.
Name some substances in our daily use which contain water of crystallization.
Answer:

• Alum (Potash alum – K₂SO₄.Al₂(SO₄)₃.24H₂O)
• Borax (Na₂B₄O₇.10H₂O)
• Epsom salt (Magnesium sulphate MgSO₄.7H₂O)
• Barium chloride (BaCl₂.2H₂O)
• Sodium sulphate (Glauber’s salt Na₂SO₄.10H₂O)

Question 4.
Give the uses of radioactive isotopes in the measurement of thickness, density and level.
Answer:
Measurement of thickness, density and level:

• It is necessary to maintain the required thickness in the manufacture of aluminium, plastic, iron sheets of differing thickness.
• In the manufacturing process, a radioactive substance is placed on one side and an instrument to measure radiation on the other.
• The radiation read by the measuring instrument varies with the thickness of the sheet.
• Material inside a packing can also be examined by the same technique.

Question 5.
Give the uses of radioactive isotopes in Luminescent paint and radioluminescence.
Answer:
Luminescent paint and radioluminescence:

• The radioactive substances radium, promethium, tritium with some phosphour are used to make certain objects visible in the dark, for example, the hands of a clock, and certain other objects.
• Krypton-85 is used in HID (High Intensity Discharge) lamps while promethium-147 is used in portable X-ray units as the source of beta rays.

Question 6.
Give the uses of radioactive isotopes in Field of agriculture.
Answer:
Field of agriculture:

• The genes and chromosomes that give seeds properties like fast growth, higher productivity, etc. can be modified by means of radiation.
• The radioactive isotope cobalt-60 is used for food preservation.
• Onions, potatoes are irradiated with gamma rays from cobalt-60 to prevent their sprouting.
• Strontium-90 is used as a tracer in the research on various crops.

Question 7.
Give the uses of dyes.
Answer:
Uses of dyes :

• They are used for colouring cloth and hair.
• Fluorescent colours are used to make street boards that are visible at night.
• Dyes are used to polish leather shoes, purses and chappals.

Question 8.
What are the adverse effects of dyes?
Answer:
Adverse effects dyes :

• Dyeing hair can have adverse effects like hair fall, damage to hair texture, burning of skin, adverse effect on eyes, etc.
• Lipstick contains a dye named carmine. It does not affect lips but causes stomach disorders.
• Excessive use of plants for making natural dyes results in deterioration of the environment.

Question 9.
Give the uses of teflon.
Answer:
Uses of teflon :

• Teflon is a poor conductor of electricity. Therefore, Teflon clad wires and parts are used in high technology electronic instruments.
• It is used for making non-stick kitchenware.
• The coloured metal sheets of two-wheelers and four-wheelers are given a Teflon coating to protect them from damage due to high temperature and rain.

Question 10.
What is ceramic? Give examples.
Answer:

• Ceramic is a heat resistant substance formed by kneading an inorganic substance in water and then shaping it and hardening it by heating.
• Pots made by a potter, Mangalore roofing tiles, construction bricks, pottery, terracotta articles are some examples of common ceramic articles that we see around.

Question 11.
Give the uses of ceramics.
Answer:

• Ceramics can withstand high temperatures without decomposing. Ceramic is brittle, water-resistant and an electrical insulator.
• Therefore, it is used in electrical instruments, for coating the interior of a kiln, the outer surfaces of ships and blades of jet engines.
• A certain type of ceramic tiles are fixed on the outer layer of a space shuttle. Some types of ceramics are used as superconductors.

Question 12.
What is brine? What happens when ^th of this solution is evaporated?
Answer:

• The 25% aqueous solution of salt is called saturated brine.
• When th of this solution is evaporated the dissolved salt gets crystallized and salt gets separated from the solution.

Question 13.
What is baking soda? Give its chemical name and molecular formula.
Answer:

• Baking soda is a white non-crystalline powder.
• Its chemical name is sodium hydrogen carbonate or sodium bicarbonate and its molecular formula is NaHC03.

Question 14.
Give two uses of Blue vitriol.
Answer:

• Blue vitriol is used in the blood test for diagnosing anaemia.
• Bordeaux mixture which is a mixture of slaked lime and blue vitriol is used as a fungicide on fruits like grapes and musk melon.

Question 15.
What is radioactivity and what are radioactive substances?
Answer:

• Elements with a high atomic number such as uranium, thorium, radium have a property of spontaneously emitting invisible, highly penetrating and high energy radiation. This property is called radioactivity.
• A substance having this property is called a radioactive substance.

Question 16.
What can you say about the uses of radioactive isotopes?
Answer:

• It is a misconception that radioactive elements are used only for making an atom bomb.
• Radioactive isotopes are used in various fields such as scientific research, agriculture, industry, medicine, etc.
• Radioactive substances are used in two ways.
• By using the radiation alone.
• By using the radioactive element itself.

Question 17.
Give the uses of radioactive isotopes in Radiography.
Answer:

• Internal cracks and voids in cast iron articles and iron solder can be detected with the help of gamma rays.
• For this purpose, isotopes like cobalt-60, iridium-192 are used in the radiography camera.
• This technique is used for detecting flaws in metalwork.

Question 18.
Give the uses of radioactive isotopes in ceramic articles.
Answer:

• Luminous colours are used to decorate ceramic tiles, utensils, plates, etc.
• Earlier uranium oxide was used in these paints.

Question 19.
What is a dye?
Answer:
The coloured substance which on applying to an article, imparts that colour to the article, is called a dye

Question 20.
What is done to fix a dye on the cloth ?
Answer:

• A mordant is to be used to fix the colour after dyeing a cloth.
• A mordant is a chemical binding agent that adheres well to both the fibers and the dye.

Question 21.
What is Teflon? Give its chemical name.
Answer:

• Teflon is the polymer of tetrafluoroethylene.
• Its chemical name is polytetrafluoroethylene (C₂F₄)_n

Question 22.
What is powder coating? Why is it done?
Answer:

• Powder coating is a method of applying a layer harder than paint on the surface of plastic, medium density fibre (MDF).
• Board and iron object to make them attractive, durable and to prevent rustihg respectively.

Question 23.
Give the properties of ceramics.
Answer:

• Ceramics can withstand high temperatures without decomposing.
• Ceramic is brittle, water resistant and an electrical insulator.

Question 24.
How is bone china made? How is it different from porcelain?
Answer:

• Bone china is made by adding some ash of animal bones in the mixture of china clay, feldspar and fine silica while making porcelain.
• This ceramic is harder than porcelain.

Question 25.
What compounds are used instead of clay for making advanced ceramic?
Answer:
Oxides like Alumina (Al₂O₃), Zirconia (ZrO₂) Silica (SiO₂) and some other compounds like silicon carbide (SiC), boron carbide (B₄C) are used instead of clay for making advanced ceramic.

Question 26.

What is sintering?
Answer:

• Advanced ceramics requires a temperature of 1600 to 1800 °C and an oxygen-free atmosphere for firing.
• This process is called sintering.

Write short notes on :

Question 1.
Chernobyl disaster.
Answer:

• On 26th April 1986, the graphite reactor in the Chernobyl atomic power plant exploded, and suddenly the radioactive isotopes and radiation came out.
• Due to this episode, radioactive isotopes entered the human body through water and land and caused genetic disorders.
• These got carried further into the next generation.
• Thyroid disorders increased in children as well as adults.
• As a result, the incidence of throat diseases is greater there than in other places.

Question 2.
Food colours.
Answer:

• Food colours are mixed in most soft drinks and foodstuffs available in the market.
• These food colours are in the form of powders, gels and pastes.
• Food colours are used in domestic as well as commercial products.
• Certain colours and essences are added to ice cream, ice candies, sauces, fruit juices, cold drinks, pickles, jams and jellies.
• Food colours are often found to be added to packaged meat (chicken, mutton), chilli powder, turmeric, sweets and other similar substances so as to give them a good colour.
• Food colours are natural as well as artificial.
• The food colours prepared from seeds, beetroot, flowers and fruit concentrate are natural.
• Tetrazene, sunset yellow are artificial food colours used extensively.
• However, over-consumption of artificial food colours can be detrimental to health. Therefore, usage of natural food colours is always good.

Question 3.
Anodizing.
Answer:

• A protective layer is formed naturally on the surface of aluminium metal by reaction with oxygen in air.
• In the anodizing process, this layer can be made of the desired thickness.
• Anodizing is done by electrolysis.
• Dilute sulphuric acid is taken in the electrolytic cell and the aluminium article is dipped in it as the anode.
• When an electric current is passed, hydrogen gas is released at the cathode and oxygen gas at the anode.
• A reaction with oxygen occurs and a layer of hydrated aluminium oxide is formed on the anode, i.e. the aluminium article.
• This layer can be made attractive by adding colour in the cell during electrolysis.

Answer the following questions:

Question 1.
What are salts? Give their source.
Answer:

• The ionic compounds which do not contain H+ and OH ions and contain only one kind of cation and anion are called simple salts.
• For example, Na₂SO₄, K₃PO₄, CaCl₂.
• The sea is said to be a rich source of salts of various elements such as chlorine, sodium, magnesium, potassium, calcium, bromine.
• The important salts found in sea water are:
  (a) Sodium chloride
  (b) Magnesium chloride
  (c) Magnesium sulphate
  (d) Potassium chloride
  (e) Calcium carbonate
  (f) Magnesium bromide

Question 2.
Which are the three kinds of salts depending on their pH value? How are they formed?
Answer:
The three kinds of salts depending on their pH value are:

Neutral salts:
Salt is neutral when its pH value is 7. Such a salt is made from a strong acid and a strong base.

Acidic salts:
The pH value of a salt made from a strong acid and a weak base is less than 7 and it is acidic.

Basic salts:
The pH value of a salt made from a weak acid and strong base is more than 7 and it is basic.

Question 3.
Which is the most used salt? What is its chemical name? How is it formed?
Answer:

• Table salt, or common salt, which gives a salty taste to food, is the most used of all salts.
• Its chemical name is Sodium chloride.
• Sodium chloride is formed by a neutralization reaction between sodium hydroxide and hydrochloric acid.
• Chemical reaction
• This is a neutral salt and the pH value of its aqueous solution is 7.

Question 4.
How is bleaching powder obtained?
Answer:

• Bleaching powder is obtained by the reaction of chlorine gas with slaked lime.
• Chemical reaction

Question 5.
How is hard water from well converted to soft water?
Answer:

• The hard water from a well or a bore-well becomes soft on adding washing soda and we come to know this from the lather formed on it.
• The hardness of water is due to the presence of chlorides and sulphates of calcium and magnesium in it.
• Na₂CO₃ is added to it to soften such water and make it suitable for use.
• The reaction with Na₂CO₃ causes the formation of insoluble carbonate salts of magnesium and calcium.
• Chemical reaction
  MgCl_2(aq) + Na₂CO_3(s) → MgCO_3(s) + 2NaCl_(s) Magnesium Sodium Magnesium Sodium chloride carbonate carbonate chloride

Question 6.
How is washing soda obtained from sodium carbonate?
Answer:

• Sodium carbonate is a water soluble salt of sodium.
• Crystalline sodium carbonate, on keeping, loses its water of crystallization readily and a white powder is obtained.
• This powder is called washing soda.
• Chemical reaction

Question 7.
How is soap prepared? Why it does not form lather with hard water?
Answer:

• When oil or animal fat is boiled with an aqueous solution of sodium or potassium hydroxide, sodium or potassium salts of carboxylic acids (fatty acids) are formed.
• These salts are called soap.
• When soap is mixed with hard water, calcium and magnesium salts of fatty acids are formed.
• These being water insoluble, they form a precipitate and that is why lather is not formed.

Question 8.
What are the harmful effects of artificial food colours?
Answer:

• Food colours added to pickles, jams and sauces contain small quantities of lead and mercury. These can be harmful for those who consume these products on a regular basis.
• Diseases like ADHD (Attention Deficit Hyperactivity Disorder) can affect children due to excessive consumption of foods with added food colours.

Question 9.
Which is the main source of colour for preparing a natural dye?
Answer:

• Plants are the main source of colour for preparing a natural dye.
• Roots, leaves, flowers, bark, fruits, seeds, fungus and pistils are used for making dyes.
• In Kashmir a very good dye is made from saffron, which is used to dye fibers from which saris, shawls and dresses are made.
• These are very costly. The use of henna leaves to colour hair is safe for health.

Question 10.
How are artificial colours harmful to us?
Answer:

• We regularly use artificial colours on Rang Panchami.
• The red colour used on Rang Panchami is very dangerous.
• It contains a high proportion of mercury in it.
• This poses risks like blindness, skin cancer, asthma, itching of the skin, permanent blocking of sweat pores, etc.
• Therefore, it is necessary that artificial colours are used cautiously.

Question 11.
What are the harmful effects of deodorants?
Answer:

• Aluminium – Zirconium compounds are the most harmful chemicals in deodorants. Disorders like headache, asthma, respiratory disorders, heart disease are likely to occur without our knowledge.
• There is a possibility of various skin disorders and also skin cancer due to the aluminium chlorohydrates.

Question 12.
How is a ceramic article made?
Answer:

• When clay is kneaded in water, shaped and then fired in a kiln at a temperature of 1000 to 1150 °C, a porous ceramic is formed.
• To overcome the porosity, the fired object is covered with finely ground glass powder suspended in water (glaze) and is then fired again. As a result, the surface of the ceramic becomes shiny and its porosity disappears.

Question 13.
What is porcelain? How is it made?
Answer:

1. Porcelain is a hard, translucent and white coloured ceramic. It is made by using the white clay called kaolin, found in China. Glass, granite and the mineral feldspar is mixed with kaolin and kneaded with water.
2. The resulting mixture is shaped and fired in a kiln at a temperature of 1200 to 1450 °C. On firing again after glazing, beautiful articles of porcelain are obtained.

Answer the following questions:

Question 1.
What are the constituents of baking powder? Where is the baking powder used?
Answer:

• Baking powder consist of 30% sodium bicarbonate, 5-12% monocalcium phosphate and 21-26% sodium aluminium sulphate.
• Baking powder is a leavening agent and is used for increasing the volume and lightening the texture of baked goods.

Question 2.
Take a piece of coloured cloth. Put some saturated solution of bleaching powder on a small part and observe what changes take place in the colour of the cloth.
Answer:
When bleaching powder is added to a piece of coloured cloth, the fabric looses its colour due to the oxidising reaction of the chlorine present in the bleaching powder.

Answer in detail:

Question 1.
Give the properties and uses of Sodium chloride.
Answer:
Properties and uses of sodium chloride:

• Common salt is a colourless and crystalline ionic compound. There is no water of crystallization in its crystalline structure.
• It is a neutral salt, salty in taste.
• This compound is used for the production of salts like Na₂CO₃, NaHCO₃.
• When an electric current is passed through a saturated solution of sodium chloride (brine), it is electrolysed and hydrogen gas is released at the cathode while chlorine gas is released at the anode.
• This method is used for production of chlorine gas. In this method an important basic compound NaOH is formed in the cell.
  2NaCl + 2H₂O → 2NaOH + Cl₂↑ + H₂↑
• When salt is heated to a high temperature (about 800 °C), it melts. This is called the fused state of the salt.
• When fused salt is electrolysed, chlorine gas is released at the anode and liquid sodium metal, at the cathode.

Question 2.
Give the properties and uses of Bleaching Powder.
Answer:
Properties and uses bleaching powder:

• Bleaching powder is a yellowish-white coloured solid substance.
• Its chemical name is Calcium oxychloride.
• It has a strong odour of chlorine gas.
• It is used for disinfection of drinking water at the water works and the water in the swimming pool.
• It is used for bleaching of cloth.
• It is used for disinfection by the road side and garbage sites.
• Dilute sulphuric acid and dilute hydrochloric acid react rapidly with bleaching powder to release chlorine gas completely.
  CaOCl₂ + H₂SO₄ → CaSO₄ + Cl₂ ↑ + H₂O CaOCl₂ + 2HCl → CaCl₂ + Cl₂ ↑ + H₂O
• Calcium oxychloride reacts slowly with carbon dioxide to form calcium carbonate and chlorine.
  CaOCl₂ + CO₂ → CaCOs + Cl₂ ↑

Question 3.
Explain with neat labelled diagram the nature of radioactive radiation.

Answer:

• When radioactive radiations are allowed to pass through two oppositely charged plates they get separated. This method was introduced by Rutherford in 1902.
• Rutherford and Willard studied the radiation emitted by radioactive substances.
• For this purpose, the rays were allowed to pass through an electrical field and a photographic plate was held in their path.
• It was found that the radiation was divided into three types.
• One type of radiation deviated slightly towards the negatively charged plate, while the second type of radiation deviated substantially towards the positively charged plate.
• However, the third type of radiation did not deviate at all in the electrical field.
• The rays which deviated slightly toward negatively charged plate are called alpha rays.
• Those which deviate substantially towards the positively charged plate are called beta rays and those which did not deviate at all are called gamma rays.

Question 4.
Give the characteristics of alpha, beta and gamma rays.
Answer:
Characteristics of alpha, beta and gamma rays are as given in the table.

Question 5.
Give the uses of radioactive isotopes in Medical science.
Answer:
Medical science:

• Polycythemia: The red blood cell count increases in the disease polycythemia. Phosphorus- 32 is used in its treatment.
• Bone cancer: Strontium-89, strontium-90, samarium-153 and radium-223 are used in the treatment of bone cancer.
• Hyperthyroidism: Enlargement of thyroid gland, weight loss in spite of appetite, insomnia are the symptoms of hyperthyroidism.
• It occurs due to overproduction of hormones by the thyroid gland. Iodine-123 is used in the treatment of hyperthyroidism.
• Tumour detection: Boron-10, iodine-131, cobalt-60 are used in the treatment of brain tumour, while arsenic-74 is used in detection of small tumours in the body.

Question 6.
What are the hazards of radioactive substances and radiation?
Answer:

• The central nervous system is affected by radioactive radiations.
• Hereditary defects are generated by bombardment of radiation on D.N.A in the body.
• Radioactive radiation can penetrate the skin, and causes diseases like skin cancer, leukemia.
• The radiative pollutants created due to explosions enter the body through air and it is difficult to control them.
• The radioactive pollutants released in the sea enter the bodies of fishes and through them enter the human body.
• The radioactive paint on the watch can cause cancer.
• The radioactive isotopes strontium-90 can enter the body through plants, fruits, flowers, cereals, milk, etc. and cause diseases like bone cancer, leukemia.

Question 7.
Why are deodorant used? Give their types and content.
Answer:

• Body odour is caused by the bacterial decomposition of the sweat. A deodorant is used to prevent this odour.
• Deodorants contain parabens (methyl, ethyl, propyl, benzyl and butyl) and also alcohol in large proportions. Aluminium compounds and silica are also used.
• Types of deodorants are :
  (a) Ordinary deo: It contains a smaller proportion of aluminium. It decreases the odour of the sweat.
  (b) Antiperspirant deo : This decreases the extent of sweating. It contains about 15% of aluminium chlorohydrate. It clogs the sweat pores on the skin.
  (c) Clinical deo : Some people sweat heavily and it has harmful effects on the skin. Clinical deo is meant for such people. It contains 20 to 25% aluminium. It is used during the night.

Question 8.
Explain how powder coating is done.
Answer:

• Powder coating is a method of applying a layer harder than paint on the surface of an iron object to prevent rusting.
• In this method, a polymer resin, a pigment and some other ingredients are melt, mixed, cooled and ground into a uniform powder.
• This powder is sprayed on the polished metal surface by electrostatic spray deposition (ESD).
• In this method, the particles of the powder are given an electrostatic charge due to which a uniform layer of the powder sticks to the metal surface.
• Then the object is heated in the oven along with the coating.
• A chemical reaction occurs in the layer, resulting in the formation of long cross-linked polymeric chains.
• This powder coating is highly durable, hard and attractive.
• Powder coating can be done on plastic and medium density fibre (MDF) board in day to day use as well.

Balbharati Maharashtra State Board 9th Std Science Textbook Solutions 

• Information Communication Technology (ICT) Class 9 Science Textbook Solutions
• Reflection of Light Class 9 Science Textbook Solutions
• Study of Sound Class 9 Science Textbook Solutions
• Carbon: An Important Element Class 9 Science Textbook Solutions
• Substances in Common Use Class 9 Science Textbook Solutions
• Life Processes in Living Organisms Class 9 Science Textbook Solutions
• Heredity and Variation Class 9 Science Textbook Solutions
• Introduction to Biotechnology Class 9 Science Textbook Solutions
• Observing Space: Telescopes Class 9 Science Textbook Solutions

Std 9 Science Chapter 1 Laws of Motion Question Answer Maharashtra Board

Balbharti Maharashtra State Board Class 9 Science Solutions Chapter 1 Laws of Motion Notes, Textbook Exercise Important Questions and Answers.

Class 9 Science Chapter 1 Laws of Motion Question Answer Maharashtra Board

Class 9 Science Chapter 1 Laws of Motion Textbook Questions and Answers

1. Match the first column with appropriate entries in the second and third columns and remake the table.

2. Clarify the differences

A. Distance and displacement
Answer:

B. Uniform and non-uniform motion.
Answer:

3. Complete the following table.

4. Complete the sentences and explain them.

a. The minimum distance between the start and finish points of the motion of an object is called the ……….. of the object.
b. Deceleration is ………………………. acceleration
c. When an object is in uniform circular motion, its ………………………. changes at every point.
d. During collision ………………………. remains constant.
e. The working of a rocket depends on Newton’s ………………………. law of motion.

5. Give scientific reasons.

a. When an object falls freely to the ground, its acceleration is uniform.
Answer:

• When the body falls freely to the ground, there are equal changes in velocity of the body in equal intervals of time.
• Thus the acceleration of the body is constant, and it possesses uniform acceleration.

b. Even though the magnitudes of action force and reaction force are equal and their directions are opposite, their effects do not get cancelled.
Answer:

• Action and reaction forces act on different bodies.
• They don’t act on the same body, hence they cannot cancel each other’s effect.
• Hence, even though the magnitudes of action force and reaction force are equal, they do not cancel each other.

c. It is easier to stop a tennis ball as compared to a cricket ball, when both are traveling with the same velocity.
Answer:

• Momentum of an object depends on its mass as well as its velocity.
• Cricket ball is heavier than a tennis ball. Although they are thrown with the same velocity, cricket ball has more momentum than a tennis ball.
• The force required to stop a cricket ball is more than a tennis ball.
• Hence it is easier to stop a tennis ball than a cricket ball moving with same velocity.

d. The velocity of an object at rest is considered to be uniform.
Answer:

• When a body is at rest there is no change in velocity.
• A body with constant velocity is said to be in uniform motion.
• Hence, the state of rest is an example of uniform motion.

6. Take 5 examples from your surroundings and give an explanation based on Newton’s laws of motion.

7. Solve the following examples.

a) An object moves 18 m in the first 3 s, 22 m in the next 3 s and 14 m in the last 3 s. What is its average speed? (Ans: 6 m/s)
Answer:
Given:
Total distance (d) = 18 + 22 + 14 = 54 m
Total time taken (t) = 3 + 3 + 3 = 9 sec
To find:
Average speed = ?

The object moves with an average speed of 6 m/s.

b) An object of mass 16 kg is moving with an acceleration of 3 m/s². Calculate the applied force. If the same force is applied on an object of mass 24 kg, how much will be the acceleration? (Ans: 48 N, 2 m/s²)
Answer:

The force acting on the 1 body is 48 N and the acceleration of the 2” body is 2 m/s²

c) A bullet having a mass of 10 g and moving with a speed of 1.5 m/s, penetrates a thick wooden plank of mass 90 g. The plank was initially at rest. The bullet gets embedded in the plank and both move together. Determine their velocity. (Ans: 0.15 m/s)
Answer:


The plank embedded with the bullet moves with a velocity of 0.15 m/s.

d) A person swims 100 m in the first 40 s, 80 m in the next 40 s and 45 m in the last 20 s. What is the average speed? (Ans: 2.25 m/s²)

Answer:
Given:
Total distance (d) = 100 + 80 + 45 = 225 m
Total time taken (t) = 40 + 40 + 20 = 100 sec
To find:
Average speed =?

The person swims with an average speed of 2.25 m/s.

Class 9 Science Chapter 1 Laws of Motion Intext Questions and Answers

(i) Who will take less time to reach the school and why?
Answer:
Prashant will take less time as the path followed by him is the shortest.

(a) Every morning, Swaralee walks round the edge of a circular field having a radius of 100 m. As shown in figure (a), if she starts from the point A and takes one round, how much distance has she walked and what is her displacement?
Answer:
Radius (r) = 100 m
Distance covered = Circumference of the circle
= 2 nr
= 2 x 3.14 x 100
= 628 m
Displacement = 0 m (Shortest distance between initial and final position is zero)

(b) If a car, starting from point P, goes to point Q (see figure 1.9) and then returns to point P, how much distance has it travelled and what is its displacement?

Answer:
Distance covered = PQ + QP
= 360 + 360
= 720 m
Displacement = 0 m (The shortest distance between initial and final position is zero)

Class 9 Science Chapter 1 Laws of Motion Additional Important Questions and Answers

(A) Choose and write the correct option:

Laws Of Motion Class 9 Questions And Answers Maharashtra Board Question 1.
The displacement that occurs in unit time is called …………….. .
(a) displacement
(b) distance
(c) velocity
(d) acceleration
Answer:
(c) velocity

Laws Of Motion Class 9 Maharashtra Board Exercise Answers  Question 2
The unit of velocity in the SI system is …………….. .
(a) cm/s
(b) rn/s²
(c) um/s²
(d) rn/s
Answer:
(d) m/s

Laws Of Motion Class 9 Maharashtra Board  Question 3.
v² = u² + 2as is the relation between and …………….. .
(a) speed and velocity
(b) distance and acceleration
(c) displacement and velocity
(d) speed and distance
Answer:
(c) displacement and velocity

Class 9 Science Notes Chapter 1 Laws Of Motion Question 4.
…………….. is the relation between displacement and time.
(a) v = u + at
(b) v² = u² + 2as
(c) s = ut + 1/2 at²
(d) v = u + 2as
Answer:
(c) s = ut + 1/2 at²

Class 9 Science Chapter 1 Laws Of Motion Question Answer Question 5.
The force necessary to cause an acceleration of 1 m/s² in an object of mass 1 kg is called …………….. .
(a) 1 dyne
(b) 1 m/s
(c) 1 Newton
(d) 1 cm/s
Answer:
(c) 1 Newton.

9th Science Chapter 1 Laws Of Motion Question 6.
Even if the displacement of an object is zero, the actual distance traversed by it …………….. .
(a) may not be zero.
(b) will be zero
(c) will be constant
(d) will be infinity
Answer:
(a) may not be zero

Question 7.
If the velocity changes by equal amounts in equal time intervals, the object is said to be in …………….. .
(a) uniform acceleration
(b) uniform velocity
(c) non-uniform acceleration
(d) non-uniform motion
Answer:
(a) uniform acceleration

Question 8.
If an object is moving with a uniform velocity …………….. .
(a) its speed remains the same, but direction of motion changes
(b) its speed changes but direction of motion is same
(c) its speed and direction both change
(d) its speed and direction both remain the same
Answer:
(d) its speed and direction both remain the same

Question 9.
is an example of positive acceleration.
(a) A stone is thrown vertically upwards
(b) A stone falls freely towards the earth
(c) Brakes are applied by the truck driver
(d) The train arriving at the station
Answer:
(b) a stone falls freely towards the earth

Question 10.
An object continues to remain at rest or in a state of uniform motion along a straight line unless an …………….. acts on it.
(a) internal imbalanced force
(b) external unbalanced force
(c) internal balanced force
(d) external balanced force
Answer:
(b) external unbalanced force

Question 11.
The …………….. is proportional to the applied force and it occurs in the direction of the force.
(a) change of momentum
(b) rate of change of velocity
(c) change of velocity
(d) rate of change of momentum
Answer:
(d) rate of change of momentum

Question 12.
…………….. is a relative concept.
(a) Motion
(b) Direction
(c) Power
(d) Acceleration
Answer:
(a) Motion

Question 13.
A body is said to be in motion if it changes its …………….. with respect to its surroundings.
(a) position
(b) direction
(c) speed
(d) force
Answer:
(a) position

Question 14.
A body is said to be at …………….. if it does not change its position with respect to its surroundings.
(a) Motion
(b) Rest
(c) Gravity
(d) Force
Answer:
(b) Rest

Question 15.
…………….. is the length of the actual path travelled by an object in motion while going from one point to another.
(a) Distance
(b) Displacement
(c) Speed
(d) Velocity
Answer:
(a) Distance

Question 16.
The distance covered by a body in unit time is called its …………….. .
(a) velocity
(b) speed
(c) displacement
(d) rest
Answer:
(b) speed

Question 17.
S.I. unit of speed is …………….. and in C.G.S unit it is …………….. .
(a) m/s and cm/s
(b) km/s and cm/s
(c) m/s and mm/s
(d) m/s and nm/s
Answer:
(a) m/s , cm/s

Question 18.
The distance travelled in a particular direction by an object in unit time is called its …………….. .
(a) velocity
(b) speed
(c) displacement
(d) rest
Answer:
(a) velocity

Question 19.
Units of speed and velocity are the
(a) Same
(b) Different
(c) Greater than each other
(d) Unequal
Answer:
(a) same

Question 20.
…………….. . is related to distance, while …………….. is related to displacement.
(a) Gravity and magnetism
(b) Speed and force
(c) Speed and velocity
(d) Motion and rest
Answer:
(c) Speed, velocity

Question 21.
If an object covers equal distances in equal time intervals, it is said to be moving with …………….. speed.
(a) Uniform
(b) Non uniform
(c) Changing
(d) Random
Answer:
(a) uniform

Question 22.
If an object covers unequal distances in equal time Intervals, it is said to be moving with speed.
(a) Uniform
(b) Non uniform
(c) Changing
(d) Random
Answer:
(b) non uniform

Question 23.
The rate of change of velocity is called
(a) Speed
(b) Acceleration
(c) Velocity
(d) Rest
Answer:
(b) acceleration

Question 24.
Speed of light in dry air is …………….. m/s.
(a) 3 x 10⁷
(b) 3 x 10⁸
(c) 3 x 10⁹
(d) 3 x 10³
Answer:
(b) 3 x 10⁸

Question 25.
When velocity of a body increases, its acceleration is …………….. .
(a) Negative
(b) Zero
(c) Positive
(d) Equal
Answer:
(c) positive

Question 26.
When velocity of a body decreases, its acceleration is …………….. .
(a) Negative
(b) Zero
(c) Positive
(d) Equal
Answer:
(a) negative

Question 27.
Negative acceleration is also called or
(a) Deceleration or retardation
(b) Deceleration or acceleration
(c) acceleration or retardation
(d) Zero
Answer:
(a) deceleration or retardation

Question 28.
In case of motion, object travels equal …………….. in equal intervals of time.
(a) Uniform, distance
(b) Non-Uniform, distance
(c) Uniform, displacement
(d) Uniform, displacement
Answer:
(a) uniform, distances

Question 29.
Motion of an object was studied by …………….. .
(a) Sir Albert Einstein
(b) Sir Thomas Edison
(c) Sir Isaac Newton
(d) Sir Ravindranath Tagore
Answer:
(c) Sir Issac Newton

Question 30.
When an object moves in a circular path with uniform speed, its motion is …………….. motion.
(a) Non uniform circular
(b) Random circular
(c) Uniform circular
(d) Uniform linear
Answer:
(c) uniform circular

Question 31.
When a coin moves along a circular path, the direction of its motion at every point is …………….. .
(a) Circular
(b) Concave
(c) Tangential
(d) Convex
Answer:
(c) tangential

Question 32.
For all uniformly accelerated motions, the velocity-time graph is a …………….. .
(a) Curved line
(b) Straight line
(c) Negative line
(d) Positive line
Answer:
(b) straight line

Question 33.
In the distance-time graph, the slope of the straight line indicates …………….. .
(a) Acceleration
(b) Velocity
(c) Speed
(d) Rest
Answer:
(b) velocity

Question 34.
The first equation of motion gives relation between …………….. and time.
(a) Acceleration
(b) Velocity
(c) Speed
(d) Rest
Answer:
(b) velocity

Question 35.
Newton’s first law explains the phenomenon of
(a) Rest
(b) Inertia
(c) Speed
(d) Velocity
Answer:
(b) inertia

Question 36.
…………….. cause a change in the state of an object at rest or in uniform motion.
(a) Balanced forces
(b) Zero forces
(c) Unbalanced forces
(d) None of them
Answer:
(c) Unbalanced forces

Question 37.
To describe an object’s momentum, we must specify its …………….. and …………….. .
(a) Mass and displacement
(b) Mass and direction
(c) Mass and velocity
(d) Mass and acceleration
Answer:
(c) mass and velocity

Question 38.
…………….. is the product of mass and velocity of an object.
(a) Speed
(b) Acceleration
(c) Momentum
(d) Force
Answer:
(c) Momentum

Question 39.
The rate of change of momentum is proportional to the applied …………….. .
(a) Balanced force
(b) Unbalanced force
(c) Mass
(d) Velocity
Answer:
(b) unbalanced force

Question 40.
S.I. unit of momentum is
(a) kg cm/s
(b) kg m/s
(c) gm/s
(d) m/s
Answer:
(b) kg m/s

Question 41.
…………….. is always conserved in a collision.
(a) Force
(b) Power
(c) Speed
(d) Total momentum
Answer:
(d) Total momentum

Question 42.
When a bullet is fired from the gun, the gun moves in backward direction. This motion is called as …………….. .
(a) Momentum
(b) Velocity
(c) Acceleration
(d) Recoil
Answer:
(d) Recoil

Question 43.
In CGS system, the unit of force is …………….. .
(а) Newton
(b) Watt
(c) Horse power
(d) Dyne
Answer:
(d) Dyne.

 (B) 1. Find the odd man out:

Question 1.
Displacement, Force, Momentum, Mass
Answer:
Mass

Question 2.
Speed, Power, Energy, Acceleration
Answer:
Acceleration

Question 3.
Newton’s 1st law, Newton’s 2nd law, Newton’s 3rd law, Kepler’s laws of motion
Answer:
Newton’s 3rd law

(B) 2. Find out the correlation

Question 1.
Speed zero: Body at rest :: Negative acceleration : Retardation
Answer:
Retardation

Question 2.
Displacement : Vector quantity :: Distance : Scalar quantity
Answer:
Vector quantity

Question 3.
When body comes to rest at the end of the motion : Final velocity is zero :: When body is at rest at the starting of motion : Initial velocity is zero
Answer:
Initial velocity is zero

Question 4.
Uniform circular motion: Displacement is zero :: Uniform velocity : Acceleration is zero
Answer:
Displacement is zero

Question 5.
Inertia : Newton’s 1st law :: Rate of change of momentum : Newton’s 2nd law
Answer:
Newton’s 2nd law

Question 6.
Balanced force : Body at rest :: Force equation : Mass x acceleration
Answer:
Body at rest

(B) 3. Distinguish between:

Question 1.
Positive acceleration and Negative acceleration
Answer:

Question 2.
Scalar quantity and Vector quantity
Answer:

Question 3.
Balanced force and Unbalanced force
Answer:

(B) 4. State whether the following statements are true or false:

Question 1.
The velocity of a body is given by the distance covered by it in unit time in a given direction.
Answer:
True

Question 2.
Displacement is a scalar quantity.
Answer:
False

Question 3.
Uniform acceleration means that the body is moving with a uniform velocity.
Answer:
False

Question 4.
The direction of acceleration can be opposite to that of velocity.
Answer:
True

Question 5.
Work is a vector quantity.
Answer:
False

Question 6.
Displacement is always greater than distance.
Answer:
False

Question 7.
The distance and displacement are equal only if, motion is along a straight path.
Answer:
True

Question 8.
If an object experiences acceleration, a force is acting on it.
Answer:
True

Question 9.
A train pulling out from a station is in uniform motion.
Answer:
False

Question 10.
If a bus in motion is suddenly stopped, the passengers fall backwards.
Answer:
False

Question 11.
If a single force is acting on an object, it will always accelerate.
Answer:
True

Question 12.
In circular motion, direction of motion is tangential.
Answer:
True

Question 13.
The inertia of a body is measured in terms of its mass.
Answer:
True

(B) 5. Name the following:

Question 1.
The scientist who summarized motion in a set of equations of motion.
Answer:
Isaac Newton

Question 2.
Motion of an object along a circular path with uniform speed.
Answer:
Uniform circular motion

Question 3.
What is the backward motion of the gun called?
Answer:
Recoil

Question 4.
The motion in which the object covers equal distance in equal intervals of time.
Answer:
Uniform motion

Question 5.
S. I. unit of acceleration.
Answer:
m/s²

Question 6.
CGS unit of momentum
Answer:
g cm/s

(B) 6. Answer the following in one sentence:

Question 1.
When is acceleration said to be positive?
Answer:
When the velocity of a body increases, acceleration is said to be positive acceleration.

Question 2.
What is negative acceleration?
Answer:
When the velocity of a body decreases, acceleration is said to be negative acceleration.

Question 3.
What is the direction of velocity of an object performing uniform circular motion?
Answer:
The direction of velocity is along the tangential direction to its position.

Question 4.
Give the mathematical expression used to determine velocity of an object moving with uniform circular motion.
Answer:
is the expression used to determine velocity of a body moving with uniform circular motion.

Question 5.
What kind of force keeps the body at rest?
Answer:
Balanced force keeps the body at rest.

Question 6.
Which law of motion gives the measure of force?
Answer:
Newton’s second law of motion gives the measure of force.

Question 7.
What are vectors and scalars?
Answer:
Scalars are physical quantities having magnitude only whereas, vectors are physical quantities having both magnitude and direction.

Question 8.
Which of the quantities distance, speed, velocity, time and displacement are scalars and which are vectors?
Answer:
Distance, speed and time are scalars displacement and velocity are vectors.

Give formula:

Question 1.
Force =
Answer:
Mass x Acceleration = ma

Question 2.
Final velocity (v) =
Answer:
Initial Velocity + (Acceleration x Time) = u + at

Question 3.
Displacement (s) =
Answer:

Question 4.
Final velocity² (v²) =
Answer:
Initial Velocity² + 2 x Acceleration x Displacement = u² + 2as

Question 5.
velocity of an object moving with uniform circular motion =
Answer:

Give scientific reasons:

Question 5.
Motion is relative.
Answer:

• The motion of an object depends on the observer, hence a body may appear moving for one person and at the same time at rest for another one.
• Hence, motion is relative.

Question 6.
Newton’s first law of motion is called as law of inertia.
OR
Heavier objects offer more inertia.
Answer:

• Inertia is related to the mass of the object.
• As mass is the quantity of matter in a body, we need to exert more force to push a heavier body.
• Hence heavier objects offer more inertia.
• As the same property is described by Newton’s first law of motion, it is called as Law of Inertia.

Question 7.
The launching of a rocket is based on Newton’s third law of motion.
Answer:

• Newton’s third law of motion states that ‘Every action force has an equal and opposite reaction force which acts simultaneously.’
• When the fuel in a rocket is ignited, it bums as a result of chemical reaction.
• The exhaust gases escape with a great force in the backward direction.
• It exerts an equal and opposite reaction force on the rocket, due to which the rocket moves in the forward direction.
• Thus, the principle of launching of rocket is based on Newton’s third law of motion.

Solve the following numerical:

Question 1.
An athlete is running on a circular track. He runs a distance of 400 m in 25 s before returning to his original position. What is his average speed and velocity?
Answer:
Given:
Total distance travelled = 400 m
Total displacement = 0, as he returns to his original position.
Total time = 25 seconds.
To find:
Average speed = ?
Average velocity = ?

The athlete runs at an average speed of 16 m/s and velocity 0 m/s.

Question 2.
An aeroplane taxies on the runway for 30 s with an acceleration of 3.2 m/s² before taking off. How much distance would it have covered on the runway?
Answer:


The distance covered on the runway is 1440 m.

Question 3.
A kangaroo can jump 2.5 m vertically. What must be the initial velocity of the kangaroo?
Answer:
Given:
a = 9.8 m/s², s = 2.5 m, v = 0,
To find:
u = ?
Formula:
v² = u² + 2as
Solution:
v² = u² + 2as
0² = u² + 2 x (-9.8) (2.5) : (Negative sign is used as the acceleration is in the direction opposite to that of velocity.)
0= u² – 49 u²
= 49 u
= 7 m/s

The initial velocity of the kangaroo must be 7 m/s.

Question 4.
A motorboat starts from rest and moves with uniform acceleration, if it attains the velocity of 15 m/s in 5s, calculate the acceleration and the distance travelled in that time.
Answer:
Given:
Initial velocity, u = 0
Final velocity, v = 15 m/s time, t = 5 s.
To find:
Acceleration (a) = ?
Distance (s) = ?
Solution:
From the first equation of motion

From the second equation of motion, the distance covered will be

The acceleration is 3 m/s² and distance travelled is 37.5 m.

Question 5.
The mass of a cannon is 500 kg and it recoils with a speed of 0.25 m/s. What is the momentum of the cannon?
Answer:
Given:
mass of the cannon = 50 kg
recoil speed = 0.25 m/s
To find:
Momentum = ?
Formula:
Momentum = m x v
Solution:
Momentum = m x v
= 500 x 0.25
= 125 kg m/s

The momentum of cannon is 125 kg m/s

Answer the following in short:

Question 1.
Explain the three different ways to change the velocity.
Answer:
As velocity is related to speed and direction, it can be changed by :

• Changing the speed while keeping the direction constant.
• Changing direction while keeping speed constant.
• Changing both speed as well as direction of motion.

Question 2.
Explain what is positive, negative and zero acceleration.
Answer:

• Positive Acceleration: When the velocity of an object increases, the acceleration is positive. In this case, the acceleration is in the direction of velocity.
• Negative Acceleration: When the velocity of an object decreases with time, it has negative acceleration. Negative acceleration is also called deceleration. Its direction is opposite to the direction of velocity.
• Zero Acceleration: If the velocity of the object does not change with time, it has zero acceleration.

Question 3.
What inference do we draw from the velocity-time graph for a uniformly accelerated motion?
Answer:

• From velocity-time graph we can infer whether velocity changes by equal amounts in equal intervals of time or not.
• Thus, for all uniformly accelerated motion, the velocity – time graph is a straight line and slope of the line gives the acceleration.
• For non-uniformly accelerated motion, velocity-time graph can have any shape according to variation in velocity with respect to time.

Question 4.
State the three equations of motion and give the relationship explained by them.
Answer:

• v = u + at: This is the relation between velocity and time.
• s = ut + 1/2 at² : This is the relation between displacement and time
• v² = u² + 2as : This is the relation between displacement and velocity.

Question 5.
What are the implications of Newton’s Third Law of motion?
Answer:

• Action and reaction are terms that express force.
• These forces act in pairs. One force cannot exist by itself.
• Action and reaction forces act simultaneously.
• Action and reaction forces act on different objects. They do not act on the same object and hence cannot cancel each other’s effect.

Question 6.
Explain recoil and recoil velocity. Derive its expression.
Answer:

• Let us consider the example of a bullet fired from a gun. When a bullet of mass nij is fired from a gun of mass m₂, its velocity becomes v₂, and its momentum becomes m^. Before firing the bullet, both the gun and the bullet are at rest. Hence, total initial momentum is zero.
• According to Newton’s third law of motion, the total final momentum also has to be zero. Thus, the forward-moving bullet causes the gun to move backward after firing.
• This backward motion of the gun is called its recoil. The velocity of recoil, v₂ is such that,
  

Complete the flow chart: