CBSE Worksheet for Chapter - 12 Pollution of Air and Water Class 8

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Find CBSE Worksheet for chapter-12 Pollution of Air and Water class 8

CLASS-8

BOARD: CBSE

BIOLOGY Worksheet - 12

TOPIC: Pollution of Air and Water

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1. ___________ and ___________ are two common water-borne diseases.

2. The oxygen carrying capacity of blood decreases due to _________ gas.

3. Corrosion of statues and monuments occurs due to:

(a) Photochemical smog

(b) CO

(d) Methane

4. Percentage of nitrogen in air is –

(a) 77.02%

(b) 78.09%

(d) 74.09%

5. Which one of the following is not a major source of pollution?

(a) Radioactive substances

(b) Oil spills

(d) A bucket full of hot water poured into a river

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

7. Why does the increased level of pollutants in the water affect the survival of aquatic organisms?

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

9. Describe the threat to the beauty of the Taj Mahal.

10. Explain ‘The Ganga Action Plan’.

Solutions: to worksheet-12 Topic- Pollution of Air and Water

1. Cholera and Typhoid

2. Carbon monoxide

3. (c) Acid rain

4. (b) 78.09%

5. (d) A bucket full of hot water poured into a river

6. Sulphur dioxide combines with water vapours to produce sulphuric acid which corrodes metals and etches marble. This sulphuric acid comes down with water as ‘Acid Rain’. It causes damage to plants and other organisms. In humans, it might cause skin pigmentation. It also damages rare monuments and buildings.

7. The increased level of pollutants in the water, effect her survival of aquatic organisms due to organic pollutants lead to bacterial growth which reduces the amount of oxygen dissolved in water and this in turn kills the fish and destroys the aquatic life.

8. Water which looks clean and clear may still have disease carrying microorganisms and dissolved impurities. So is essential to purify water before drinking by boiling or using water purifiers.

9. Case study on Taj Mahal:

• The industries located in and around Agra like rubber processing, automobile, chemicals and especially the Mathura oil refinery, have been responsible for producing pollutants like SO₂ and NO₂.

• These gases react with the water vapour present in the atmosphere to form sulphuric acid and nitric acid. This acid drops down with rain making the rain acidic. This is called Acid Rain.

• Acid rain corrodes the marble of the movement. The phenomenon is called ‘Marble cancer’.

• Suspended particulate matter, such as the soot particles emitted by Mathura oil refinery has & contributed towards the yellowing of the marble.

• The Supreme Court has taken several steps to save the Taj. It has ordered industries to switch to cleaner fuels like CBG and LPG. Morever, the automobiles should switch over to unleaded petrol in the Taj zone.

10. An ambitious plan to save the river called the Ganga Action Plan’ was launched in 1985. It aimed to reduce the pollution levels in the river. However, the increasing population and industrialization have already damaged the mighty river beyond repair.