Q8 / 66 · JEE Advanced 2008 (Paper 2) · Chemistry

The correct stability order for the following species is

A
(II) $>$ (IV) $>$ (I) $>$ (III)
B
(I) $>$ (II) $>$ (III) $>$ (IV)
C
(II) $>$ (I) $>$ (IV) $>$ (III)
Correct answer
D
(I) $>$ (III) $>$ (II) $>$ (IV)

Solution

I $>$ III $>$ II $>$ IV $+M$-effect, hyperconjugation $(6 \mathrm{Hs})$ and $+$ I-effect (2 Me groups) $+M$-effect, hyperconjugation ( $3 \mathrm{Hs}$ ) and $+I$-effect (1 Me group) $\overbrace{2^{\circ} \text { carbocation) }}^{+}$Hyperconjugation (5Hs) and +I-effect Hyperconjugation (2Hs) and $+I$ effect

Hence, the correct answer is option: 'D'.

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