NCERT Class VIII Science Solutions: Chapter 18-Pollution of Air and Water Part 4

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Question 22:

Match the items of Column A with those of Column B.

Match the Items of Column a and Column B.(Q)
Match the items of Column A and Column B.(Q)

Column A

Column B

Sulphur dioxide

Damage ozone layer

Carbon dioxide

Reduces oxygen-carrying capacity of blood

Carbon monoxide

Acid rain.

Chlorofluorocarbons

Greenhouse gas

Answer:

Match the Items of Column a and Column B.(A)
Match the items of Column A and Column B.(A)

Column A

Column B

Sulphur dioxide

c Acid rain.

Carbon dioxide

d Greenhouse gas

Carbon monoxide

b Reduces oxygen-carrying capacity of blood

Chlorofluorocarbons

a Damage ozone layer

Question 23:

Find out the wrong statements and write them in their correct form.

  1. We can survive for some time without air but we cannot survive even for a few minutes without food.

  2. A brick kiln emits lot of smoke and other harmful gases causing air pollution.

  3. Carbon monoxide is produced by complete burning of fuels such as coal, petrol, and diesel.

  4. Chlorination is a commonly used chemical method for killing germs in water.

  5. Water which is suitable for drinking is called soft water.

Answer:

  1. We can survive for some time without air but we cannot survive even for a few minutes without food. (Wrong)

    Hint: We can survive for some time without food but we cannot survive even for a few minutes without air.

  2. A brick kiln emits lot of smoke and other harmful gases causing air pollution. (Correct)

  3. Carbon monoxide is produced by complete burning of fuels such as coal, petrol, and diesel. (Wrong)

    Hint: Carbon monoxide is produced by incomplete burning of fuels such as coal, petrol, and diesel.

  4. Chlorination is a commonly used chemical method for killing germs in water. (Correct)

  5. Water which is suitable for drinking is called soft water. (Wrong)

    Hint: Water which is suitable for drinking is called potable water.

Question 24:

In the following statements, the underlined words are jumbled up. Write them in their correct form.

  1. Air contains ginroten and gonexy.

  2. Vehicles produce high level of pollutants like carbon dioxide, nitrogen oxides, nobrac moondexi and mosek.

  3. Carbon dioxide, thaneme, nitrous oxide and water vapour are known as heengrouse sesga.

  4. Gangotri glacier in Himalaya has started melting because of lablog ringwam.

  5. Whenever harmful substances such as wagese, toxic chemicals, silt, etc. get mixed with water, the water becomes potdulle.

Answer:

  1. Air contains nitrogen and oxygen.

  2. Vehicles produce high level of pollutants like carbon dioxide, nitrogen oxides, carbon monoxide and smoke.

  3. Carbon dioxide, methane, nitrous oxide and water vapour are known as greenhouse gases.

  4. Gangotri glacier in Himalaya has started melting because of global warming.

    Image of global warming

    Image of Global Warming

    Image of global warming

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

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