“Stability of carbocation depends upon the electron releasing inductive effect of groups adjacent to positively charged carbon atom involvement of neighbouring groups in hyper-conjugation and resonance.” Write structures of various carbocation that can be obtained from 2-methylbutane. Arrange these carbocation in order of increasing stability.

Question

Philoid · Accepted Answer

There are four possible carbocation structures for 2-methylbutane. And they are:

Now, the stability order is found to be:

(III) > (II) > (I) > (IV)

This is because (III) is tertiary carbocation, (II) is secondary carbocation, (I) and (IV) are primary, but as the number of alpha hydrogen in (I) is more than that of (IV) (as more number of alpha hydrogen leads to more stability of carbocation; in hyper-conjugation.)