Question

In both alkyl halides and aryl halides, the halogen (X) atom is attached directly to the carbon atom. They are expected to exhibit similar reactivity. However, aryl halides are comparatively very little reactive, particularly towards nucleophilic substitution reaction. for example, hydrolysis of ethyl chloride occurs by simply boiling with aqueous KOH. ON the other hand, the alkaline hydrolysis of chlorobenzene requires a very high temperature (623K) as well as a very high pressure.
Q. Among the following which has weakest C-X bond?
A. Benzyl bromide
B. Bromobenzene
C. Vinyl bromide
D. Benzyl chloride.

Answer 1

Correct Answer - A
`C_(6)H_(5)CH_(2)-Br` has weakest `C-Br` bond because `C_(6)H_(5)overset(o+)(C)H_(2)` ion can be easily resonance stabilised. Moreover, `C-Br` can cleave most readily.