Question

An incorrect statement with respect to $\text{S}_{\text{N}}1$ and $\text{S}_{\text{N}}2$ mechanism for alkyl halide is

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

Answer 1

Answer: (B)

$\text{S}_{\text{N}}1$ reaction occurs through the formation of carbocation as intermediate. Hence, rearrangement occurs in $\text{S}_{\text{N}}1$ reaction and not in $\text{S}_{\text{N}}2$ reaction. $\text{S}_{\text{N}}1$ reaction is favoured in presence of a polar protic solvent and a weak nucleophite. These reactions can be catalysed by the some Lewis is acid. A strong nucleophile is an aprotic solvent increases the rate of $\text{S}_{\text{N}}2$ reaction. Hence, option $\left(\right.\text{B}\left.\right)$ in incorrect.