Question

Which among the following is NOT a feature of \(\text{SN}^2\) mechanism ?

• A. Single step mechanism
• B. Backside attack of nucleophile
• C. Formation of planar carbocation intermediate
• D. Involves simultaneous bond breaking and bond forming

Hint:

SN2 is a one-step concerted process with no carbocation intermediate.

Answer 1

The Correct Option is C

Step 1: Compare the two mechanisms:
SN1 has two steps with a planar carbocation intermediate and gives racemisation. SN2 has one step with a transition state and gives inversion of configuration.

Step 2: Check each option:
(A) single step: SN2. (B) backside attack: SN2. (D) simultaneous bond breaking and forming: SN2. (C) planar carbocation intermediate: SN1.

Step 3: Choose:
The odd one out, which is NOT a feature of SN2, is (C).

Final Answer:
Option (C) is not an SN2 feature. \[ \boxed{\text{(C)}} \]