Question

The stability of carbocations

follows the order

(a) III < IV < II < I

(b) III < IV < I < II

(c) IV < III < II < I

(d) IV < III < I < II

Answer 1

Answer is : (b) III < IV < I < II

As the size of alkyl group goes on increasing, the + I effect exerted by it becomes strong and, thus the carbocation will be more stable. So, among 1°, 2° and 3° carbocation, 3° will be most stable.

Although (CH₃)₂ \(\overset{+}{C}\)(OCH₃) will be highly stable among the given carbocations due to resonance stabilisation.

Thus, the correct order of stability of carbocations will be