Question

An incorrect statement with respect to $S_{N}1$ and $S_{N}2$ mechanisms for alkyl halide is

• A. Competing reaction for an $S_{N}2$ reaction is rearrangement
• B. A weak nucleophile and a protic solvent increases the rate or favours $S_{N}1$ reaction
• C. A strong nucleophile in an aprotic solvent increases the rate or favours $S_{N}2$ reaction.
• D. $S_{N}1$ reactions can be catalysed by some Lewis acids

Answer 1

Answer: (A)

This problem includes concept of $S_{N}1$ and $S_{N}2$ reaction and factor affecting $S_{N}1$ and $S_{N}2$ reaction.

During $S_{N}2$ reaction of alkyl halide, inversion of configuration takes place instead of rearrangement.

While $S_{N}1$ reaction occurs through the formation of carbocation intermediate which is favoured by the presence of lewis acid and aprotic solvent.

Reatrangement of product is also possible in this case.

$C{H}_{3}X+KOH(aq)⟶C{H}_{3}OH+KX$