See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Radical Stability Analysis **Step 1: Identify the radical type in each option** - (1) Aryl radical (phenyl with Me substituent) - (2) Benzylic radical (primary $\cdot CH_2$ attached to benzene ring) - (3) Allylic radical (primary $\cdot CH_2$ adjacent to C=C) - (4) Tertiary alkyl radical (quaternary carbon with unpaired electron) **Step 2: Apply stability ordering** Radical stability follows: **Aryl > Benzylic > Allylic > Tertiary alkyl > Secondary > Primary** This is because: - **Aryl radicals** have the unpaired electron in a $p$-orbital conjugated with the aromatic $\pi$ system, providing exceptional resonance stabilization - The benzene ring's $\pi$-electrons delocalize the unpaired electron density **Step 3: Compare options** - (4) Tertiary alkyl: No resonance stabilization - (3) Allylic: Some conjugation but with C=C only - (2) Benzylic: Good resonance, but secondary carbon - (1) Aryl: Maximum resonance through aromatic ring **Conclusion:** Option **(1)** is the most stable free radical due to resonance stabilization of the unpaired electron by the aromatic benzene ring system.