Question

Which of the following events does NOT occur during $S{N}^2$ reaction mechanism?

• A. Backside attack of nucleophile
• B. Formation of carbonium ion
• C. One step continuous process
• D. $100\%$ inversion of configuration

Answer 1

Answer: (B)

Formation of carbonium ion

The $S_{N}2$ reaction involves displacement of a leaving group by a nucleophile. When the nucleophile attacks in a $S_{N}2$ reaction, it is on the opposite side to the position of the leaving group. As a result, the reaction proceeds with an inversion of configuration.

It is the one-step reaction and 100% inversion takes place.

Hence, the correct option is $\text{B}$.