A B a Oil spill i helps the sedimentation of suspended particles in water b Ceramic candles i i a water-borne disease c Alum i i i reduces the transmission of light through water d Bleaching powder i v water filter e Typhoid v disinfects water

Oil tankers carry petroleum by sea from one country to another. Oil spills out in tanker accidents or otherwise. The film of oil that floats over the water badly affects the transmission of light through the water body. This affects the process of photosynthesis in aquatic plants. Ceramic candles is act as water filter. It has fine pores which allow only the water to pass through, but not the suspended particles. Alum facilitates the removal of suspended particles from water by sedimentation. The bleaching powder slowly reacts with water to give chlorine, which kills the germs. CaOCl 2 bleaching powder + H 2 O water → Ca ( OH ) 2 calcium hydroxide + Cl 2 chlorine Water is the carrier of several microorganisms that cause common water-borne diseases like typhoid, dysentery, cholera and hepatitis. The microorganisms responsible for these diseases are present in the excreta of infected persons. When the excreta are discharged into a water body, the water body becomes a source of infection and the disease spreads. A B a Oil spill i i i reduces the transmission of light through water b Ceramic candles i v water filter c Alum i helps the sedimentation of suspended particles in water d Bleaching powder v disinfects e Typhoid i i a water-borne disease

E M B I B E

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q B

EASY

8th CBSE

IMPORTANT

Earn 100

How does carbon monoxide affect us?

Important Questions on Pollution of Air and Water

MEDIUM

8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q C

Name three pollutants (except dust and soot) of air and mention their sources.

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q C

Describe eutrophication.

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q D

_____ is formed by the complete combustion of carbon. (Write the name of the compound)

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q D

An increase in the

{CO}_{2}

level in the air causes the _____ effect.

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q E

The ozone layer in our atmosphere protects us from the bad effects of

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q E

Which of the following is an oxygen-demanding waste?

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q E

Which of the following is/are used for disinfecting water?

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8th CBSE

IMPORTANT

Basic Science for Class 8>Chapter 16 - Pollution of Air and Water>Exercises>Q F

A	B
$(a)$ Oil spill	$(i)$ helps the sedimentation of suspended particles in water
$(b)$ Ceramic candles	$(i i)$ a water-borne disease
$(c)$ Alum	$(i i i)$ reduces the transmission of light through water
$(d)$ Bleaching powder	$(i v)$ water filter
$(e)$ Typhoid	$(v)$ disinfects water

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