Question

Which of the following order is correct for the stability of these carbocations?

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

Answer 1

Answer: (A)

I>III>II

In structure$\left(i\right)$, the cation is in resonance. Hence its stability is more than other structures because they don't have resonance.

In structure $\left(ii\right)$ and $\left(iii\right);\left(iii\right)$ is more stable than $\left(ii\right)$ because of more number of carbons atoms which as positive inductive effect.

$\left(i\right)>\left(iii\right)>\left(ii\right).\to$ Stability of carbocations order.