Chapter 14 - Environmental Chemistry

Assertion (A) : If BOD level of water in a reservoir is less than 5 ppm it is
highly polluted.
Reason (R) : High biological oxygen demand means low activity of bacteria
in water.
(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

Assertion (A) : Excessive use of chlorinated synthetic pesticides causes soil
and water pollution.
Reason (R) : Such pesticides are non-biodegradable.
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(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

Assertion (A) : Ozone is destroyed by solar radiation in upper stratosphere.
Reason (R) : Thinning of the ozone layer allows excessive UV radiations
to reach the surface of earth.
(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

Assertion (A) : Carbon dioxide is one of the important greenhouse gases.
Reason (R) : It is largely produced by respiratory function of animals and
plants.
(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

Assertion (A) : The pH of acid rain is less than 5.6.
Reason (R) : Carbon dioxide present in the atmosphere dissolves in rain
water and forms carbonic acid.
(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

In the following questions a statement of Assertion (A) followed by a statement
of Reason (R) is given. Choose the correct option out of the choices given
below each question.

Assertion (A): Green house effect was observed in houses used to grow
plants and these are made of green glass.
Exemplar Problems, Chemistry 182
Reason (R) : Green house name has been given because glass houses are
made of green glass.
(i) Both A and R are correct and R is the correct explanation of A.
(ii) Both A and R are correct but R is not the correct explanation of A.
(iii) Both A and R are not correct.
(iv) A is not correct but R is correct.

Match the pollutants given in Column I with their effects given in Column II.
Column I Column II
(i) Phosphate fertilisers in water (a) BOD level of water increases
(ii) Methane in air (b) Acid rain
(iii) Synthetic detergents in water (c) Global warming
(iv) Nitrogen oxides in air (d) Eutrophication

Match the activity given in Column I with the type of pollution created by it
given in Column II.
Column I (Activity) Column II (Effect)
(i) Releasing gases to the atmosphere (a) Water pollution
after burning waste material
containing sulphur.
(ii) Using carbamates as pesticides (b) Photochemical smog,
damage to plant life,
corrosion to building
material, induce breathing
problems, water pollution
(iii) Using synthetic detergents for (c) Damaging ozone layer
washing clothes
(iv) Releasing gases produced by (d) May cause nerve diseases
automobiles and factories in the in human.
atmosphere.
(v) Using chlorofluorocarbon compounds (e) Classical smog, acid rain,
for cleaning computer parts water pollution, induce
breathing problems,
damage to buildings,
corrosion of metals.

Match the pollutant(s) in Column I with the effect(s) in Column II.
Column I                                           Column II
(i) Oxides of sulphur                         (a) Global warming
(ii) Nitrogen dioxide                           (b) Damage to kidney
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(iii) Carbon dioxide                         (c) ‘Blue baby’ syndrome
(iv) Nitrate in drinking water               (d) Respiratory diseases
(v) Lead (e) Red haze in traffic and
congested areas

What are the sources of dissolved oxygen in water?

What are biodegradable and non-biodegradable pollutants?

During an educational trip, a student of botany saw a beautiful lake in a
village. She collected many plants from that area. She noticed that villagers
were washing clothes around the lake and at some places waste material
from houses was destroying its beauty.
After few years, she visited the same lake again. She was surprised to find that
the lake was covered with algae, stinking smell was coming out and its water
had become unusable.Can you explain the reason for this condition of the
lake?

On the basis of chemical reactions involved, explain how do
chlorofluorocarbons cause thinning of ozone layer in stratosphere.

Ozone is a toxic gas and is a strong oxidising agent even then its presence in
the stratosphere is very important. Explain what would happen if ozone from
this region is completely removed?

Green house effect leads to global warming. Which substances are responsible
for green house effect?

What is an insecticide?

Discuss the water pollution caused by industrial water?

What is pneumoconiosis? 

What is the desirable concentration of fluoride ion (F-) in drinking water?

What is the effect of excess of SO₄^2- ion in drinking water

What should be the pH of drinking water?

What are pesticides?

Define green chemistry.

What does the amount of BOD signify?

What is BOD?

How can photochemical smog be controlled?

Why does rain water normally have a pH of about 5.6? When does it
become acid rain,

When does rain water become acid rain?

What is the composition of photochemical smog?

What is PAN?

Which acid is present is the acid rain?

Name two gases which form acid rain.

Name two air pollutants which forms photochemical smog.

The London smog is caused in which season and time of the day?

What is smog?

What are the ill effects of ozone hole?

Which disease is caused due to ozone layer depletion?

What is the effect of CFC’s on ozone layer?

Name the factors that are responsible for the depletion of ozone layer?

What is ‘greenhouse effect’? How does it affects the global climate?

Which zone is called ozonosphere?

Give one main reason of ozone depletion?

What is the effect of CFC’s on ozone layer?

List gases which are responsible for green house effect?

What is harmful effect of nitrogen dioxide?

What are the ill-effects of hydrocarbons?

Why is carbon monoxide considered to be poisonous?

What are the harmful effects of oxides of nitrogen in oxygen?

What includes stratospheric pollutants? Give examples

What are the diseases caused by sulphur dioxide?

Name some gaseous air pollutants

What is the role of ozone layer in the stratosphere?

What is troposphere?

For your agricultural field or garden you have developed a compost producing pit. Discuss the process in the light of bad odour, flies and recycling of wastes for a good produce.

How can domestic waste be used as manure?

A large number of fish are suddenly found floating dead on a lake. There is no evidence of toxic dumping but you find an abundance of phytoplankton. Suggest a reason for the fish kill.

What would have happened if the greenhouse gases were totally missing in the earth's atmosphere? Discuss.

What do you mean by green chemistry? How will it help decrease environmental pollution?

What are pesticides and herbicides? Explain giving examples.

Do you observe any soil pollution in your neighbourhood? What efforts will you make for controlling the soil pollution?

What do you mean by Biochemical Oxygen Demand (BOD)?

Have you ever observed any water pollution in your area? What measures would you suggest to control it?

What are the major causes of water pollution? Explain.

What do you mean by ozone hole? What are its consequences?

What are the reactions involved for ozone layer depletion in the stratosphere?

What are the harmful effects of photochemical smog and how can they be controlled?

Write down the reactions involved during the formation of photochemical smog.

What is smog? How is classical smog different from photochemical smog?

Statues and monuments in India are affected by acid rain. How?

List gases which are responsible for greenhouse effect.

Carbon monoxide gas is more dangerous than carbon dioxide gas. Why?

Explain tropospheric pollution in 100 words.

Define environmental chemistry.