Lakhmir Singh & Manjit Kaur - Science

Book: Lakhmir Singh & Manjit Kaur - Science

Chapter: 18. Pollution of Air and Water

Subject: Chemistry - Class 8th

Q. No. 48 of Questions Based on High Order Thinking Skills (HOTS)

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Match the items given in column I with one or more items given in column II:

Column I

Column. II

(i) Prevents photosynthesis

(a) Sewage dumped in river

(ii)Damage ozone layer

(b) Excess fertilizer in fields

(iii) Produce acid rain

(c) Carbon dioxide in air

(iv) Kill fish by deoxygenating water

(d) Dust in air

(v) Causes water borne diseases

(e) CFCs

(vi) Leads to global warming in air

(j) Sulphur dioxide

(i) Prevents photosynthesis - (d) Dust in air

Dust reduces the photosynthesis in plants due which causes a decrease in energy production in plants causing the plants to suffer.

(ii) Damage ozone layer - (e) CFCs

Chlorofluorocarbons used in refrigerators, air conditioners and aerosol sprays are responsible to deplete the ozone layer in the atmosphere. Ozone layer protects us from harmful ultraviolet rays of the sun.

(iii) Produce acid rain - (j) Sulphur dioxide

Sulphur dioxide and nitrogen dioxide which reacts with water vapors in the atmosphere to form sulphuric acid and nitric acid. These acids combine with rain and makes the rain water acidic. This is called Acid rain.

(iv) Kill fish by deoxygenating water - (b) Excess fertilizer in fields

The fertilizers act as nutrients for the algae to grow. When these algae die, they act as a nutrient for decomposers like bacteria. As a result of this process, a lot of oxygen in the water gets used up and leads to the deficiency of Oxygen in the water. This may kill the aquatic organisms including fish.

(v) Causes water borne diseases - (a) Sewage dumped in river

Sewage water contains bacteria, viruses, protozoa, fungi and parasites(worms) which may cause diseases like cholera, typhoid and jaundice.

(vi) Leads to global warming in air - (c) Carbon dioxide in air

Carbon dioxide is the gas which is mainly responsible for causing global warming. Carbon dioxide traps heat and does not allow it to escape into space causing an increase in the average temperature of the earth’s atmosphere.

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