Question

The increasing order of stability of the following free radicals is ______.

Options

• \[\ce{(C6H5)2\overset{\bullet}{C}H < (C6H5)3\overset{\bullet}{C} < (CH3)3\overset{\bullet}{C} < (CH3)2\overset{\bullet}{C}H}\]

• \[\ce{(CH3)2\overset{\bullet}{C}H < (CH3)3\overset{\bullet}{C} < (C6H5)2\overset{\bullet}{C}H < (C6H5)3\overset{\bullet}{C}}\]

• \[\ce{(CH3)3\overset{\bullet}{C} < (CH3)2\overset{\bullet}{C}H < (C6H5)2\overset{\bullet}{C}H < (C6H5)3\overset{\bullet}{C}}\]

• \[\ce{(C6H5)3\overset{\bullet}{C} < (C6H5)2\overset{\bullet}{C}H < (CH3)3\overset{\bullet}{C} < (CH3)2\overset{\bullet}{C}H}\]

Answer 1

The increasing order of stability of the following free radicals is `underlinebb((CH_3)_2\overset(•)(C) H < (CH_3)_3\overset(•)(C) < (C_6H_5)_2\overset(•)(C)H < (C_6H_5)_3\overset(•)(C))`.

Explanation:

The order of stability of free radicals is:

\[\ce{(C6H5)3\overset{\bullet}{C} > (C6H5)2\overset{\bullet}{C}H > (CH3)3\overset{\bullet}{C} > (CH3)2\overset{\bullet}{C}H}\]

The first two are stabilised due to resonance, while the last two are stabilised due to hyperconjugation.