Class 11 Chemistry MCQ – Environmental Chemistry

1. Which of the following is a primary pollutant?

a) Ozone
b) Sulphur dioxide
c) Peroxyacetyl nitrate
d) Formaldehyde

Answer:

b) Sulphur dioxide

Explanation:

Primary pollutants are those directly released into the atmosphere. Sulphur dioxide is a primary pollutant, while others are secondary pollutants.

2. The greenhouse effect is caused by an excess of:

a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Helium

Answer:

c) Carbon dioxide

Explanation:

The greenhouse effect results from an increase in gases like carbon dioxide which trap heat in the atmosphere.

3. Which of the following is not a consequence of acid rain?

a) Soil acidification
b) Forest damage
c) Depletion of the ozone layer
d) Damage to aquatic life

Answer:

c) Depletion of the ozone layer

Explanation:

Acid rain does not cause the depletion of the ozone layer. They are two separate environmental issues.

4. BOD stands for:

a) Biological Oxygen Demand
b) Biochemical Organic Decomposition
c) Base Organic Decomposition
d) Biochemical Oxygen Demand

Answer:

d) Biochemical Oxygen Demand

Explanation:

BOD refers to the amount of oxygen required by bacteria to decompose organic matter in water.

5. Which gas is responsible for the formation of photochemical smog?

a) Nitrogen
b) Methane
c) Carbon dioxide
d) Nitrogen oxides

Answer:

d) Nitrogen oxides

Explanation:

Nitrogen oxides, when combined with volatile organic compounds in the presence of sunlight, lead to the formation of photochemical smog.

6. The main cause of eutrophication is:

a) Heavy metals
b) Excessive nutrients
c) Organic waste
d) Industrial pollutants

Answer:

b) Excessive nutrients

Explanation:

Eutrophication is caused by an excessive amount of nutrients, often due to fertilizer run-off, leading to algal blooms.

7. Ozone layer depletion is mainly caused by:

a) Sulphur dioxide
b) Chlorofluorocarbons (CFCs)
c) Nitrogen oxides
d) Carbon monoxide

Answer:

b) Chlorofluorocarbons (CFCs)

Explanation:

CFCs are the primary culprits responsible for the depletion of the ozone layer in the stratosphere.

8. Which among the following is a non-biodegradable waste?

a) Vegetable peels
b) Paper
c) Plastic bags
d) Cow dung

Answer:

c) Plastic bags

Explanation:

Plastic bags are non-biodegradable and persist in the environment for a long time.

9. Which of the following is not a greenhouse gas?

a) Water vapor
b) Methane
c) Ozone
d) Nitrogen

Answer:

d) Nitrogen

Explanation:

While water vapor, methane, and ozone are greenhouse gases, nitrogen does not contribute to the greenhouse effect.

10. Which metal is a major contaminant in the Minamata disease?

a) Lead
b) Mercury
c) Cadmium
d) Arsenic

Answer:

b) Mercury

Explanation:

Minamata disease is caused by the consumption of seafood contaminated with methylmercury.

11. The primary source of organic pollution in freshwater is:

a) Pesticides
b) Detergents
c) Sewage
d) Industrial effluents

Answer:

c) Sewage

Explanation:

Sewage is the main source of organic pollution in freshwater systems.

12. The term "Tropospheric pollution" refers to:

a) Water pollution
b) Soil pollution
c) Air pollution at ground level
d) Radiation pollution

Answer:

c) Air pollution at ground level

Explanation:

The troposphere is the lowest layer of the atmosphere, and its pollution refers to the contamination at ground level.

13. Which of the following pollutants can cause skin cancer in humans?

a) Lead
b) Asbestos
c) UV rays
d) Sulphur dioxide

Answer:

c) UV rays

Explanation:

Excessive exposure to UV rays can increase the risk of skin cancer.

14. CNG stands for:

a) Carbon Natural Gas
b) Compressed Nitrogen Gas
c) Compressed Natural Gas
d) Carbon Nitrate Gas

Answer:

c) Compressed Natural Gas

Explanation:

CNG is a cleaner alternative fuel to traditional gasoline and diesel.

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