Question

Class 8 science ch 18- pollution of air and water... Give me que and
First one to give proper ans will get brainliest

Answer 1

Question 1:

What are the different ways in which water gets contaminated?

Answer 1:

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.

Question 2:

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

Answer 2:

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.

Question 3:

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

Answer 3:

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.

Question 4:

You are a member of the municipal body of your town.

Make a list of measures that would help your town to ensure the supply of clean water to

all its residents.

Answer 4:

We can take following measures:

 Water should be treated properly to make it free from harmful germs, chemical

and physical impurities.

 Enforce laws to treat water and chemicals before disposing into water bodies.

 Proper maintenance of pipes supplying tap water to avoid any corrosion, breakage

and leakage.

 Organize awareness programmes to keep water resources clean and make a habit

of conserving water.

Question 5:

Explain the differences between pure air and polluted air.

Answer 5:

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.

Question 6:

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

Answer 6:

When harmful gases like sulphur dioxide and nitrogen dioxide, react with the water

vapour present in the atmosphere to form sulphuric acid and nitric acid. The acids drop

down with rain, making the rain acidic. This is called acid rain.

Acid rain causes skin irritation, inhibits germination of plants, causes corrosion to bridges

and building. It changes the fertility of the soil, destroys plants and aquatic life.

Answer 2

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