Question

Carbocation which is most stable

• A. CH3CH$_2^+$
• B. CH$_3^+$
• C. C$_6$H$_5$CH$_2^+$
• D. CH$_3$CH$_2$CH$_2^+$

Answer 1

Answer: (C)

C$_6$H$_5$CH$_2^+$

Answer 2

Carbocation stability is enhanced by resonance, hyperconjugation, and inductive effects. Resonance stabilization is the most significant factor. The benzyl carbocation (C$_6$H$_5$CH$_2^+$) is stabilized by resonance with the pi electrons of the phenyl ring, which delocalizes the positive charge. The other carbocations (methyl, ethyl, n-propyl) are stabilized mainly by hyperconjugation and inductive effects, which are less effective than resonance. The methyl carbocation has no significant stabilization. Ethyl (3 alpha H) and n-propyl (2 alpha H) are primary carbocations stabilized by hyperconjugation. Resonance stabilization makes the benzyl carbocation the most stable among the given options.