NCERT Solution for class 8 Science Pollution of Air and Water

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Pollution of Air and Water Chapter 18

This solution is for class eight students. This was the understandable answers for book back exercises of class 8 Science chapter 18 Pollution of Air and Water. This covers all the questions in Pollution of Air and Water exercise. This lesson will be continued in upcoming classes and more competitive exams. For more follow

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1. What are the different ways in which water gets contaminated ?


Different ways by which water gets

ⅰ) Garbage: Plastic, Food waste and some other waste were released into the water

ⅰⅰ) Domestic waste: Oils, Detergents and other household chemicals were released into the water

ⅰⅰⅰ) Agriculture: Chemical structures fertilizers and weedicides runoff pollute the water bodies.

2. At an individual level, how can you help reduce air pollution ?


) Use public transport instead of personal cars.

ⅰⅰ) Switch to fuels such as biofuel and solar energy.

ⅰⅰⅰ) Plant more trees

ⅳ) Garbages should not burnt which makes air pollution

These are the ways by which we can reduce air pollution.

3. Clear, transparent water is always fit for drinking comment.


No, clear and transparent water is always good for drinking because it looks clean to see but it contains many microorganisms which cause diseases. So the water must be purified or boiled before drinking.

4. You are the member of municipal body of a town. Make a list of measures that will help your town to ensure the supply of clean water to all its residents.


The measures that keep our town to ensure the supply of clean water to all residents are:

ⅰ) Chemical methods want to done to purify the water.

ⅰⅰ) The surrounded area must be clean where the main water source had built.

ⅰⅰⅰ) Water tank should be cleaned at a time.

5. Explain the difference between pure air and polluted air.


The Pure air contains many gases like 78% Nitrogen, 21% Oxygen and 1% percentage of argon, carbon dioxide, Ozone, methane. When the pure air in the environment gets polluted by harmful substances such as Carbon dioxide and Nitrogen dioxide then the air gets polluted.

6. Explain circumstances leading to acid rain. How does acid rain affect us?


Oxides such as Nitrogen and Sulphur which react with the rain water to form nitric acid and sulphuric acid. These acids come down with the rain. Such rain is called acid rain.
It causes
) Damage to crops and plants
ⅰⅰ) Buildings and monuments built with white marbles like Taj Mahal
ⅰⅰⅰ) It causes skin rash for humans.

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

(a) Carbon dioxide

(b) Sulphur dioxide

(c) Methane

(d) Nitrogen


(d) Nitrogen

8.Describe the ‘GreenHouse Effect’ in your own words.


) The greenhouse effect is responsible for global warming.

ⅰⅰ) The Atmosphere includes Greenhouse gases GHGs, Water vapour H2O, Methane CH4 and Carbon dioxide CO2. These gases are responsible for trapping the 75% solar radiation to make the earth warm. This was known as greenhouse gases.

ⅰⅰⅰ) When the amount of GHGs in the atmosphere has been increased due to pollution which leads to the Enhanced Greenhouse Effect called Global warming.

9. Prepare a brief speech on global warming. You have to deliver the speech in your class.


Hi everyone,
We all know that the continuous rising of the earth’s temperature is called global warming. This causes the Earth’s average temperature to rise and causes glaciers to melt. Carbon dioxide is the main cause of the greenhouse effect due to increased combustion and deforestation in the atmosphere.
Thank you

10.Describe the threat to the beauty of the Taj Mahal.


The main threat to the Taj Mahal is acid rain. The steam mixes with nitrogen dioxide and sulfur dioxide to form acid rain, which corrodes and discolors the marble. This phenomenon is known as marble cancer.

11.Why does the increased level of nutrients in the water affect the survival of aquatic organisms?


The increased level of nutrients in the water affects the survival of aquatic organisms because the number of algae in the water body also increases. When these algae die these act as food for decomposers. It takes more oxygen in this process. It results in a decrease in the amount of dissolved oxygen in the water body. So the fish and aquatic life will die.


Materials: Metals and Non-metals Class 8 Summary

Minerals And Power Resources

Pure Substances

Is Matter Around Us Pure

Change in states of matter

States of Matter

Grip Facts

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