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JEE Advanced levelOne or more correct optionsDifficulty 3 of 3hx144

Which statements about chlorofluorocarbons are correct?

AThe fluorine radicals released are mainly responsible for ozone depletion
BCFCs are rapidly destroyed in the troposphere by rain, so little reaches the stratosphere
CThe compound $CCl X_{3} F$ is Freon-11 by the rule of 90
DIn the stratosphere, UV light breaks a $C - Cl$ bond in $CF X_{2} Cl X_{2}$ to give $Cl$ radicals that start a chain which destroys $O X_{3}$

Answer: C, D

11 + 90 = 101

gives C = 1, H = 0, F = 1 and three

Cl

, so

CCl X_{3} F

is Freon-11. CFCs are chemically inert and insoluble, so they survive to the stratosphere. There UV breaks the weaker

C - Cl

bond, not

C - F

, so chlorine radicals (not fluorine) are the catalysts.

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