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Subject :NSO    Class : Class 8

Which of the following statements are true?
(i) Cigarette smoke is a source of carbon monoxide.
(ii) Smog is a combination of smoke and fog which mainly contains CFCs.
(iii) Burning of coal releases fly ash.
(iv) Acid rain increases the pH of rivers and lakes.

A (i) and (ii)
B (i) and (iii)
C (ii) and (iv)
D (iii) and (iv)

Ans 1:

Class : Class 8
Carbon monoxide and hydrogen cyanide are another 2 highly toxic chemicals found in cigarette smoke.Fly Ash, a very fine, powdery material composed mostly of silica made from the burning of finely ground coal in a boiler.

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