Question

The correct order of increasing stabilities for the following carbocations is
(1) allyl carbocation
(2) neopentyl carbocation
(3) benzyl carbocation
(4) isobutyl carbocation

• A. $ (1) <\, (4) <\, (2) <\, (3) $
• B. $ (4) <\, (1) <\, (2) <\, (3) $
• C. $ (2) <\, (4) <\, (1) <\, (3) $
• D. $ (2) < \,(4) < \,(3) < \, (1) $

Answer 1

Answer: (C)

Allyl carbocation (stabilised by resonance)

Neopentyl carbocation :

Benzyl carbocation (stabilised by resonance)

Isobutyl carbocation :

Benzyl and allyl carbocations are much more stable due to resonance
Hence, the stability order is
Neopentyl carbocation $<$ isobutyl carbocation $<$ allyl carbocation $<$ benzyl carbocation