Chemistry Class-11: Chapter –14. Environmental Chemistry Part – 5

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V. Assertion and Reason Type

In the following questions a statement of Assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below each question.

Question: 39

Assertion (A): Greenhouse effect was observed in houses used to grow plants and these are made of green glass.

Reason (R): Greenhouse name has been given because glass houses are made of green glass.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct.

Answer: (iii)

Question: 40

Assertion (A): The pH of acid rain is less than 5.6

Reason (R): Carbon dioxide present in the atmosphere dissolves in rain water and forms carbonic acid.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct.

Answer: (ii)

Question: 41

Assertion (A): Photochemical smog is oxidizing in nature.

Reason (R): Photochemical smog contains and , which are formed during the sequence of reactions.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct.

Answer: (i)

Question: 42

Assertion (A): Carbon dioxide is one of the important greenhouse gases.

Reason (R): It is largely produced by respiratory function of animals and plants.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct.

Answer: (ii)

Question: 43

Assertion (A): Ozone is destroyed by solar radiation in upper stratosphere.

Reason (R): Thinning of the ozone layer allows excessive UV radiations to reach the surface of earth.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct

Answer: (iv)

Question: 44

Assertion (A): Excessive use of chlorinated synthetic pesticides causes soil and water pollution.

Reason (R): Such pesticides are non-biodegradable

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct.

Answer: (i)

Question: 45

Assertion (A): If level of water in a reservoir is less than 5 ppm it is highly polluted.

Reason (R): High biological oxygen demand means low activity of bacteria in water.

(i) Both A and R are correct and R is the correct explanation of A.

(ii) Both A and R are correct but R is not the correct explanation of A.

(iii) Both A and R are not correct.

(iv) A is not correct but R is correct

Answer: (iii)

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