Question

Which among the following halides will generate the most stable carbocation in a nucleophilic substitution reaction?

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

Resonance stabilization from aromatic rings significantly increases the stability of carbocations. Therefore, halides that lead to resonance-stabilized carbocations tend to undergo nucleophilic substitution reactions more readily.

Answer 1

The Correct Option is D

The stability of carbocations depends on the extent of delocalization and resonance stabilization. In the case of the halides:
- The carbocation generated from option (4) (\(\text{C}_6\text{H}_5\text{C}(\text{Br})-\text{Ph}\)) is the most stable because it benefits from resonance stabilization provided by the aromatic phenyl group.
- The carbocations formed in options (1), (2), and (3) are less stable, as they lack this additional resonance stabilization.
Thus, the most stable carbocation is generated from option (4).