Ncert Exemplar Solutions Class 8 Science Pollution of Air and Water

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Ncert Exemplar Solutions Class 8 Science Pollution of Air and Water

Welcome to NCTB Solutions. Here with this post we are going to help 8th class students for the Solutions of NCERT Exemplar Class 8 Science Book, Unit 18, Pollution of Air and Water. Here students can easily find step by step solutions of all the problems for Pollution of Air and Water, Also here our Science teacher’s are solved all the questions with easily understandable language with proper guidance so that all the students can understand easily.

Pollution of Air and Water all Question Solutions :

Multiple Choice Questions :

Question no – (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

Answer : 

Correct option – (b)

This gas is Oxygen.

Question no – (2)

Which of the following is not a source of air pollution?

Answer : 

Correct option – (c)

Windmill is not a source of air pollution.

Question no – (3)

Boojho wishes to contribute in reducing air pollution. Which vehicle should he use for going to school?

Answer : 

Correct option – (b)

Boojho should use school bus for going to school.

Question no – (4)

Which of the following is not a way to conserve water?

Answer : 

Correct option – (a)

Replace is not a way to conserve water.

Question no – (5)

The type of pollution which is likely to affect Taj Mahal in Agra to a greater extent is 

Answer : 

Correct option – (a)

The air pollution is likely to affect Taj Mahal in Agra to a greater extent.

Question no – (6)

Incomplete combustion of fuel such as petrol and diesel gives

Answer : 

Correct option – (c)

Incomplete combustion of fuel such as petrol and diesel gives Carbon Monoxide,

Question no – (7)

The phenomenon of marble cancer is due to

Answer : 

Correct option – (d)

The phenomenon of marble cancer is due to Acid rain.

Question no – (8)

Potable water is the water which is

Answer : 

Correct option – (c)

Potable water is the water which is pure and fit for drinking.

Question no – (9)

Which of the following procedures will give you water free from all impurities?

Answer : 

Correct option – (b)

Distillation will give you water free from all impurities.

Question no – (10)

A pond contains clean water. Which of the following activities will produce least pollution of water?

Answer : 

Correct option – (d)

Swimming in the pond will produce least pollution of water.

Question no – (11)

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

Answer : 

Correct option – (c)

The occasion is called Van Mahotsav.

Question no – (12)

Which of the following is not a green house gas?

Answer : 

Correct option – (a)

Nitrogen gas is not a green house gas.

Very Short Answer Questions :

Question no – (13) 

Answer : 

Chlorofluorocarbons used in refrigerators and air conditioners damage ozone layer when released in air.

Question no – (14) 

Answer : 

Eruption of volcanoes and oil refineries are two sources which cause air pollution due to suspended particulate matter.

Question no – (15) 

Answer : 

Sulphur dioxide and Nitrogen dioxide are two gases that are responsible for acid rain.

Question no – (16) 

Answer : 

This data of air quality can be used aware people of the drastic effects of air pollution upon the environment and the living organisms.

Question no – (17) 

Answer : 

Hydropower and wind energy are two alternatives sources of energy that does not causes air pollution.

Question no – (18) 

Answer : 

Arsenic and fluorides are two water pollutants which are toxic for both plants and animals.

Short Answer Questions :

Question no – (19) 

Answer : 

It is not exactly a right way to get rid of dry leaves as burning of those leaves causes air pollution. The right way should be to bury the dry leaves in a pit so that in can be used as a compost for plants.

Question no – (20) 

Answer : 

At a busy traffic intersection it is quite common for a large quantity of vehicles to stop for a vehicle. The cars together releases toxic gases in the area thus increasing the pollution level at that intersection.

Question no – (21) 

Answer : 

(a) When air is contaminated by unwanted substances which have a harmful effect on both the living and non-living, it is referred to as air pollution.

(b) Many industries are responsible for causing air pollution. Petroleum refineries are a major source of gaseous pollutants like sulphur dioxide and nitrogen dioxide.

(c) While brushing your teeth, leaving the tap running may waste several litres of water.

(d) Water which is suitable for drinking is called potable water.

(e) Water which looks clean still has disease carrying micro-organisms and dissolved impurities.

Question no – (22) 

Answer : 

Column A :  Column B : 
(a) sulphur dioxide (iv) greenhouse gas
(b) carbon dioxide (ii) reduces oxygen carrying capacity of blood
(c) carbon monoxide (iii) acid rain.
(d) chlorofluorocarbons (i) damage ozone layer

Question no – (24) 

Answer : 

(a) Air contains 78% nitrogen and 21% oxygen.

(b) Vehicles produce high level of pollutants like carbon dioxide, nitrogen oxides, carbon monoxide and smoke

(c) Carbon dioxide, Methane, nitrous oxide and water vapour are known as, greenhouse gases.

(d) Gangotri glacier in Himalaya has started melting because of global warming.

(e) Whenever harmful substances such as sewage, toxic chemicals, silt, etc. get mixed with water, the water becomes polluted.

Long Answer Questions :

Question no – (25) 

Answer : 

• CFCs stands for Chlorofluorocarbons.

• CFCs are used in Air conditioners, refrigerators and aerosol sprays.

• CFCs are considered as pollutants because they destroy the ozone layer of earth which protects us from the harmful ultraviolet rays of the sun.

Question no – (26) 

Answer : 

The industries near Taj Mahal are burning fuels that are releasing gases such as sulphur dioxide and nitrogen dioxide. This gases then react with the atmospheric water vapour to form sulphuric or nitic acid .This acid which falls in the form of rain corrodes away the marble of this monument and makes its look pale. That’s why It advised that industries should switch over to cleaner fuels such as CNG and LPG in the Taj Mahal Zone in Agra.

Question no – (27) 

Answer : 

Whenever carbon dioxide gets released into the atmosphere be it by any means, it has this ability to trap the heat and prevent it from the escaping the earth. The average temperature of the earth increase with the increase in carbon dioxide. So it is fair to say that CO2 contributes to global warming.

Question no – (28) 

Answer : 

We should plant trees and nurture the existing ones. Trees allow water to penetrate through the soil and maintain the ground water level of any area. Trees holds the soil in one place thus keeping it safe from erosion and a possible change of that place into a dessert. It not only prevents drought but also brings rain. Trees releases oxygen and absorbs carbon dioxide without which we would have became a burning oven.

Question no – (29) 

Answer : 

Water has been purified traditionally by 2 ways. One way of purifying it is by using a household candle type filter which removes all the physical impurities and the other way of purifying if is by hysical the water which kills all the microorganisms present in it.

Question no – (30) 

Answer : 

We can reduce the waste of water by doing activities activities that requires water in such a way that some of the water could be saved like washing dishes in a sink. We can reuse water that has been used in other activities such as washing vegetables to other activities such as watering the plants in our garden. Infact we could also recycle our water to by purifying it with some known methods so that if could be used again.


Other Chapter Solutions : 

👉 Crop Production and Management

👉 Microorganisms : Friend and Foe

👉 Synthetic Fibres and Plastics

👉 Materials : Metals and Non-Metals

👉 Coal and Petroleum

👉 Combustion and Flame

👉 Conservation of Plants and Animals

👉 Cell-Structure and Functions

👉 Reproduction in Animals

👉 Reaching the Age of Adolescence

👉 Force

👉 Friction

👉 Sound

👉 Chemical Effects of Electric Current

👉 Some Natural Phenomena

👉 Light

👉 Stars and Solar System

Updated: June 28, 2023 — 3:55 pm

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