Question

The order of stability of the following carbocations is:

• A. III > II > I
• B. II > III > I
• C. I > II > III
• D. III > I > II

Answer 1

The correct option is D III > I > II

Higher stability of allyl and aryl substituted methyl carbocation is due to dispersal of positive charge due to resonance.
Resonating structures of allyl carbocation:
Resonating structures of benzylic carbocation:

But in alkyl carbocation dispersal of positive charge on different hydrogen atoms is due to hyper conjugation. Hence the correct order of stability will be