Which of the following is the most stable free radical?

Explanation

Option A shows tertiary radical, tertiary radicals (radicals on a carbon atom that is directly bonded to three other carbon atoms) are generally more stable than primary (bonded to one other carbon), secondary (bonded to two other carbons), or methyl (bonded to no other carbon) radicals. This stability is attributed to the distribution of the radical electron and the resonance stabilization provided by neighboring carbon atoms. Here are a few reasons why tertiary radicals are more stable: 1. **Hyperconjugation:** Tertiary radicals benefit from hyperconjugation, where the adjacent carbon-carbon sigma (σ) bonds can delocalize the unpaired electron of the radical. This delocalization stabilizes the radical by spreading the electron density over multiple carbon atoms. 2. **Inductive Effect:** The neighboring alkyl groups exert an inductive effect, helping to stabilize the positive charge on the radical carbon. The more alkyl groups attached, the greater the stabilizing effect. 3. **Resonance Stabilization:** In some cases, tertiary radicals can exhibit resonance stabilization due to the delocalization of the unpaired electron. These combined effects make tertiary radicals more stable compared to their less substituted counterparts. Since tertiary radical is the most stable one, so option A is correct. .