Q10 / 90 · JEE Main 2024 (30 Jan Shift 2) · Chemistry

The correct stability order of carbocations is

A
${({CH}_{3})}_{3} C^{+} > {CH}_{3} - \overset{+}{C} H_{2} > {({CH}_{3})}_{2} \overset{+}{C} H > \overset{+}{C} H_{3}$
B
$\overset{+}{C} H_{3} > {({CH}_{3})}_{2} \overset{+}{C} H > {CH}_{3} - \overset{+}{C} H_{2} > {({CH}_{3})}_{3} \overset{+}{C}$
Correct answer
C
${({CH}_{3})}_{3} \overset{+}{C} > {({CH}_{3})}_{2} \overset{+}{C} H > {CH}_{3} - \overset{+}{C} H_{2} > \overset{+}{C} H_{3}$
D
$\stackrel{+\quad}{\mathrm{C}\mathrm{H}_3}>\mathrm{CH}_3-\stackrel{+ \quad}{\mathrm{C} \mathrm{H}_2}>\mathrm{CH}_3-\underset{| \atop \stackrel{ \atop }{\huge \mathrm{CH}_3}}{\stackrel{+ \quad}{\mathrm{C} \mathrm{H}}}>\left(\mathrm{CH}_3\right) \mathrm{C}^{+}$

Solution

${({CH}_{3})}_{3} \overset{+}{C} - Tertiary carbocation {({CH}_{3})}_{2} \overset{+}{C} H - Secondary carbocation {CH}_{3} - \overset{+}{C} H_{2} - Primary carbocation \overset{+}{C} H_{3} - Methyl carbocation$
Stability of carbocations depends upon the electron releasing groups. The given carbocations stability can be explained by hyperconjugation effect. More the number of alpha hydrogen, more are number of hyperconjugation structures, hence, more is the stability of carbocation.
Thus, the observed order of stability for carbocations is as follows: tertiary > secondary > primary > methyl
Hence, option C is correct.

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

The correct stability order of carbocations is

Solution

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