Question

Which one of the following halogen compounds is difficult to be hydrolysed by $S_{N}1$ mechanism?

• A. Chlorobenzene
• B. Isopropyl chloride
• C. Tertiary butyl chloride
• D. Benzyl chloride

Answer 1

The correct option is A Chlorobenzene

Vinyl and aryl halides do not ​undergo $S_{N}1$ and $S_{N}2$ reaction​. this is due to unstable aryl cation, $\pi -e^{-}$ cloud of haloarenes and partial double bond character of C-X bond​.
Partial double bond character of C-X bond developed in chlorobenzene on resonance.
X=Cl

b, c, and d can undergo $S_{n}1$ reaction easily the will form stable carbocation on loss of leaving group. Hence the correct option is a.