CBSE Class 12 Chemistry Value Based Questions Set C

Value based questions

 Chemistry

Question. Rahul observed that families from nearby localities bring loads of laundry to wash in the river practically every day, while others bring their cars, taxis and rickshaws and wash them clean by using water from the river. The same water was being consumed by people living downstream. When he tried to stop people from washing clothes and cleaning vehicles Nisar Khadim a local resident objected. “It makes no difference if we wash our cars and clothes here. It is a gift from nature,” he said. After reading the above passage, answer the following questions:

a) Who do you think is right Rahul or the taxi driver? Give a reason for your answer.
Answer: Rahul is right as he knows that detergents are surface-active agents, which tend to produce stable, copious foams in rivers. These foams generally form a thick and dense layer over the surface of the water, extending over several hundred yards of the river water. The foamy water is unsafe for both humans and fish.

b) What are the values associated with the answer?
Answer: Rahul is concerned for all types of life he is aware that chemicals in soaps and detergents are not only harmful for humans, but are also threatening to aquatic life.

Question. The Government tried to distribute oral contraceptives to the women in the villages. The villagers strongly reacted as they felt that children are God gift and consuming pills will be harmful.

a) How will you justify the villagers concern? Give a reason for your answer.
Answer: Lack of knowledge on the part of villagers make them feel that these pills would be harmful. Birth control pills contain a mixture of synthetic estrogen and progesterone which suppresses ovulation and has no ill effects on health.

b) Justify the step taken by the government giving reasons.
Answer: The Government took the right step as it will help to control population. Increasing population has caused many social problems in terms of food resourses, environmental issues and employment etc.

Question. Maya was having sleepless nights as she was under severe depression a friend advised her to take sleeping pills. She went to the chemist shop to buy the tablets but the chemist refused and asked for the doctor’s prescription. Do you feel the chemist was right?
Answer: A doctor should always be consulted before taking any medicine as most of the drugs taken in doses higher than recommended can cause harmful effect and can act as poison.

Question. A customer demanded a polybag for storing the goods he had bought but the shopkeeper handed over a paper bag instead.

a) Why the shopkeeper did not give a polybag to the customer? Give two harmful effects of polythene bags.
Answer: Plastic is not biodegradable and releases harmful dioxin into the air. People who work inplastic industries are at a greater risk for cancer and other diseases. Plastic bags discarded in fields decrease the productivity of arable land, Coloured plastic bags contain harmful toxic metals like chromium and copper which can cause allergies.

b) What is the value associated with it? 
Answer: Awareness of harmful effects of polythene bags on the environment.

Question. A survey revealed that most of the industries in Najafgarh area have not installed smokeprecipitators in the chimneys.

a) What is the use of smoke precipitators?
Answer: The cottrell smoke precipitator neutralizes the charge on the carbon particles and neutralizes them. In this way smoke coming out of the chimneys gets free from the charged particles

b) Why do you feel that it should be mandatory for industries to install smoke precipitators?
Answer: It should be made mandatory as one should be aware that carbon particles pollute the air Smoke coming out of the chimneys contains a lot of unburnt carbon particle. Smoke is the colloidal solution of the solid particles such as carbon, arsenic, dust particles etc. These particles are injurious to health and have to be precipitated . Carbon particle are charged particles and can not be precipitated. Thus a metal plate of oppositely charged particle is used for their precipitation.

Please click the below link to access CBSE Class 12 Chemistry Value Based Questions