The increasing order of stability of the following free radicals is\

Question

Professor PC Thomas Classes · Answer

(a): On the basis of hyperconjugation effect of the alkyl groups, the order of stability of free radical is as follows :\ tertiary > secondary > primary.\ Benzyl free radicals are stabilised by resonance and hence are more stable than alkyl free radicals. Further as the number of phenyl group attached to the carbon atom holding the odd electron increases, the stability of a free radical increases accordingly. i.e.,\ $\left(\mathrm{CH}_{3} ight)_{2} \stackrel{\circ}{\mathrm{C}} \mathrm{H}<\left(\mathrm{CH}_{3} ight)_{3} \stackrel{\circ}{\mathrm{C}}<\left(\mathrm{C}_{6} \mathrm{H}_{5} ight)_{2} \stackrel{\circ}{\mathrm{C}} \mathrm{H}<\left(\mathrm{C}_{6} \mathrm{H}_{5} ight)_{3} \stackrel{\circ}{\mathrm{C}}$\