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JEE Main levelSingle correct optionDifficulty 2 of 3g1122

The correct order of stability of the following carbocations is

A $(CH X_{3}) X_{3} C X^{+} > CH X_{3} CH X_{2} X^{+} > (CH X_{3}) X_{2} CH X^{+} > CH X_{3} X^{+}$
B $CH X_{3} X^{+} > CH X_{3} CH X_{2} X^{+} > (CH X_{3}) X_{2} CH X^{+} > (CH X_{3}) X_{3} C X^{+}$
C $(CH X_{3}) X_{2} CH X^{+} > (CH X_{3}) X_{3} C X^{+} > CH X_{3} CH X_{2} X^{+} > CH X_{3} X^{+}$
D $(CH X_{3}) X_{3} C X^{+} > (CH X_{3}) X_{2} CH X^{+} > CH X_{3} CH X_{2} X^{+} > CH X_{3} X^{+}$

Answer: D

The numbers of alpha hydrogens are 9, 6, 3 and 0 for tert-butyl, isopropyl, ethyl and methyl cations. More hyperconjugative structures and more +I donation give greater stability, so the order is 3 degree > 2 degree > 1 degree > methyl.

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