Question

Reactivity order of halides for dehydrohalogenation is

(a) R - F > R - Cl > R - Br > R - I

(b) R - I > R - Br > R - CI > R - F

(c) R - I > R - Cl > R > Br > R - F

(d) R - F > R - I > R - Br > R - CI

Answer 1

Correct option (b) R - I > R - Br > R - CI > R - F

Explanation :

I > Br > Cl > F → atomic radii

F, Cl, Br, I belongs to the same group orderly. Atomic radii go on increasing as the nuclear charge increases in preceeding downwards in a group. The decreasing order of bond length C - I > C - Br > C - Cl > C - F. The order of bond dissociation energy R - F > R - Cl > R - Br > R - I. During dehydrohalogenation C - I bond breaks more easily than C - F bond.So reactivity order of halides.

R - I > R - Br > R - CI > R - F