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JEE Main levelSingle correct optionDifficulty 2 of 3g1182

Which is the correct order of stability of the following free radicals?

A $(CH X_{3}) X_{2} CH^{∙} > CH X_{2} = CH - CH X_{2}^{∙} > CH X_{3} CH X_{2}^{∙} > CH X_{3}^{∙}$
B $CH X_{3}^{∙} > CH X_{3} CH X_{2}^{∙} > (CH X_{3}) X_{2} CH^{∙} > CH X_{2} = CH - CH X_{2}^{∙}$
C $CH X_{2} = CH - CH X_{2}^{∙} > CH X_{3} CH X_{2}^{∙} > (CH X_{3}) X_{2} CH^{∙} > CH X_{3}^{∙}$
D $CH X_{2} = CH - CH X_{2}^{∙} > (CH X_{3}) X_{2} CH^{∙} > CH X_{3} CH X_{2}^{∙} > CH X_{3}^{∙}$

Answer: D

The allyl radical is stabilised by resonance, which is stronger than hyperconjugation. Among alkyl radicals, stability increases with the number of alpha hydrogens: secondary (6) > primary (3) > methyl (0).

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