NCERT Solutions for Class 8 Science Chapter 18

NCERT Solutions for Class 8 Science Chapter 18 Pollution of Air and Water (Adhyay 18: Vayu ttha Jal ka Pradushan) to Study online or download free in PDF file format for new session 2020-21 based on new CBSE Syllabus and new Books.

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NCERT Solutions for Class 8 Science Chapter 18

Class:8
Subject:Science
Chapter 18:Pollution of Air and Water

Class 8 Science Chapter 18 Answers

NCERT Solutions for Class 8 Science Chapter 18 Pollution of Air and Water is given below to download free. Video Format solutions in Hindi and English Medium are also available. Download 8 Science App in Hindi and English Medium for offline use following CBSE Syllabus 2020-21.




Class 8 Science Chapter 18 Solution and Explanation

Class 8 Science Chapter 18 Important Questions for Practice

Explain the differences between pure air and polluted air.

Pure air consists of a mixture of gases in proper amount which is good for living being. If by volume, about 78% of this mixture is nitrogen, about 21% is oxygen, carbon dioxide, argon, methane, ozone and water vapour are also present in very small quantities, then it is called pure air.
When air is contaminated by unwanted substances which have a harmful effect on both the living and the non-living, it is referred to as polluted air.

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

Air pollution should be checked at individual level:
At individual level, we can plant trees as trees reduce air pollution.
We can use public transportation and encourage carpooling so that air pollution can be reduced.
Instead of going by cars and scooters for short distances, we can go by foot or by bicycles.
By saying no to crackers we can minimise air pollution as well as noise pollution.
We should not burn garbage and dry leaves. The burning of dry leaves and garbage release greenhouse gases which are responsible for global warming.

What are the different ways in which water gets contaminated?

Water gets contaminated in the following ways:
Various industrial units dispose – off wastage including harmful chemicals in rivers. These chemicals are poisonous and contaminate water.
Water gets contaminated when sewage is disposed – off (without proper treatment) in rivers.
Ground water gets contaminated by harmful insecticides and pesticides sprayed by farmers and it get mixed with drinking water through rain water.

Clear, transparent water is always fit for drinking. Comment.

Transparent water is not always fit for drinking. It may contain harmful microorganisms, soluble salts and other pollutants. Sometime water looks like pure but it contains dissolved salts or bacteria which are not good for us. We should purify water before drinking. Water can be purified with the help of water purifier or by boiling it.




Class 8 Science Chapter 18 MCQ with Answers

1. Air is a mixture of various gases. One of the gases is 21% part of the air and is essential for the survival of human beings. This gas is
(a) nitrogen
(b) oxygen
(c) ozone
(d) argon
2. A pond contains clean water. Which of the following activities will produce least pollution of water?
(a) washing clothes in the pond
(b) animals bathing in the pond
(c) washing motor vehicles in the pond
(d) swimming in the pond.
3. Which of the following is not a source of air pollution?
(a) automobile exhaust
(b) burning of firewood
(c) windmill
(d) power plant
4. Which of the following is not a way to conserve water?
(a) replace
(b) reduce
(c) reuse
(d) recycle
5. Incomplete combustion of fuel such as petrol and diesel gives
(a) nitrogen oxide
(b) sulphur dioxide
(c) carbon monoxide
(d) carbon dioxide
6. The type of pollution which is likely to affect Taj Mahal in Agra to a greater extent is
(a) air pollution
(b) water pollution
(c) soil pollution
(d) noise pollution
7. Potable water is the water which is
(a) obtained from a river.
(b) obtained from a lake.
(c) pure and fit for drinking.
(d) used only for washing clothes.
8. Boojho wishes to contribute in reducing air pollution. Which vehicle should he use for going to school?
(a) car
(b) school bus
(c) autorickshaw
(d) scooter
9. Which of the following procedures will give you water free from all impurities?
(a) adding chlorine tablets
(b) distillation
(c) boiling
(d) filtration
10. Trees help in reducing the pollution of our environment. Lakhs of trees are planted by people in the month of July every year. The occasion is called
(a) forest Conservation Day
(b) plantation month
(c) Van Mahotsav
(d) wildlife week

Answers of Important Questions (MCQ)



1 (b)
2 (d)
3 (c)
4 (a)
5 (c)
6 (a)
7 (c)
8 (b)
9 (b)
10 (c).

NCERT Solutions for Class 8 Science Chapter 18 Pollution of air and water
NCERT Solutions for Class 8 Science Chapter 18 in PDF
8 Science ch. 18 answers