Q22 of 32 Page 106

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

(a)–(iii), (b)–(iv), (c)–(ii), (d)–(i)


a) Sulphur dioxide (SO2) is one of the gases that are responsible for causing acid rain. The other gas is Nitrogen dioxide.


b) Carbon dioxide is one the 5 main greenhouse gases. The other three are: water vapor, methane, nitrous oxide and ozone.


c) Carbon monoxide reduced oxygen carrying capacity of the blood. Oxygen has hemoglobin which carries oxygen. Hemoglobin however, has a higher affinity for Carbon monoxide which means carbon monoxide can bind to hemoglobin more easily than oxygen. So when carbon monoxide is present, hemoglobin binds to it rather than to oxygen and reduces the amount of oxygen being carried by the blood.


d) CFCs or chlorofluorocarbons damage the ozone layer. CFCs are broken down by the UV radiations and release chlorine atoms. These chlorine atoms destroy the ozone.


More from this chapter

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20

The level of air pollution is higher at a busy traffic intersection. Why?

 21

Fill in the blanks with the help of words given in the bracket after each sentence.

(1) When air is contaminated by ________ substances which have a ________ effect on both the ________ and _______, it is referred to as ________.


(2) Many _______ are responsible for causing ________ pollution. Petroleum ________ are a major source of _______ pollutants like _______ and ________.


(Sulphur dioxide, refineries, industries, nitrogen dioxide, gaseous, liquid, people, air ).


(3) While ________ your teeth, leaving the ______ running may waste several ______ of water.


(tap, litres, brushing, washing, drops ).


(4) Water which is suitable for _______ is called _______ water.


(washing, bathing, drinking, potable, soft).


(5) Water which looks clean still has disease carrying _______ and _______ impurities.


(insects, micro organism, particles, dissolved, harmful).


 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, 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.


 24

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

(1) Air contains 78% ginroten and 21% goncxy.


(2) Vehicle produce high level of pollutants like carbon dioxide, nitrogen oxide, 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.