Chemistry 9th Chap 12 : Topic 6 - Maryam Publications

Chemistry Chapter 12 : Topic 6

Effects of Water Pollution

1 / 15

Excessive nitrates in water bodies primarily harm aquatic life by:

A) Converting water into distilled form

B) Enhancing fish reproduction

C) Causing oxygen depletion through algal growth

D) Increasing oxygen availability

2 / 15

Which of the following is a major long-term effect of heavy metal pollution in water?

A) Bioaccumulation in food chains

B) Improved plant growth

C) Increased dissolved oxygen

D) Reduced water hardness

3 / 15

How do water pollutants mainly affect aquatic ecosystems?

A) By increasing rainfall

B) By converting water into salt

C) By disturbing oxygen balance and food chains

D) By increasing water purity

4 / 15

Which pollutant is most directly responsible for eutrophication-like effects?

A) Distilled water

B) Nitrogen gas

C) Oxygen

D) Nitrates and phosphates

5 / 15

What is a major effect of plastic pollution in oceans?

A) Increase in fish population

B) Formation of microplastics entering food chains

C) Increase in oxygen levels

D) Reduction in water salinity

6 / 15

Why are aquatic organisms most vulnerable to water pollution?

A) They do not need oxygen.

B) They directly depend on water quality for survival.

C) They produce their own pollutants.

D) They live on land.

7 / 15

Which of the following best describes the effect of sewage discharge into rivers?

A) Purifies water naturally

B) Removes heavy metals

C) Introduces pathogens and reduces water quality

D) Improves oxygen levels

8 / 15

Oxygen depletion in water bodies mainly leads to:

A) Increased mineral content

B) Increase in aquatic biodiversity

C) Formation of pure water

D) Death of fish and aquatic organisms

9 / 15

Which human activity most directly increases water pollution?

A) Evaporation

B) Rainfall

C) Industrial discharge

D) Condensation

10 / 15

Why is untreated sewage particularly dangerous compared to chemical pollution?

A) It contains living pathogens causing diseases.

B) It only contains salts.

C) It has no biological effect.

D) It increases oxygen levels.

11 / 15

What is the indirect effect of excessive algal growth in water?

A) Increase in oxygen

B) Reduction in light penetration and oxygen depletion

C) Increase in water clarity

D) Removal of nutrients

12 / 15

Which of the following best explains biomagnification?

A) Increase of pollutant concentration along food chain

B) Removal of toxins in animals

C) Dilution of chemicals in water

D) Decrease of pollutants at higher trophic levels

13 / 15

Which pollutant is most likely to enter the human body through fish consumption?

A) Nitrogen gas

B) Heavy metals

C) Water vapor

D) Oxygen

14 / 15

What is the major environmental impact of phosphates in water?

A) Decrease in plant growth

B) Increase in oxygen permanently

C) Water purification

D) Algal bloom formation

15 / 15

Which condition increases the risk of water pollution in urban areas?

A) Filtration plants

B) Proper sewage treatment

C) Rainwater harvesting

D) Industrial waste discharge into rivers

Your score is

0%