See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Carbocation Stability Analysis **Step 1: Identify each carbocation type** - **I**: Cycloheptatrienyl cation (7-membered ring with positive charge) - **II**: Cyclohexadienyl cation (6-membered ring with positive charge) - **III**: Tropylium cation (aromatic, 6π electrons in planar ring) - **IV**: Primary benzyl cation (CH₂⁺ attached to benzene ring) **Step 2: Apply stability criteria** Carbocation stability depends on: 1. Aromaticity (most stabilizing) 2. Resonance delocalization 3. Hybridization and alkyl group effects **Step 3: Rank by stability** - **III (Tropylium)**: Aromatic 6π system → **extremely stable** (Hückel's rule: 4n+2 = 6) - **II (Cyclohexadienyl)**: Allylic system with resonance delocalization → **very stable** - **IV (Benzyl)**: Primary carbocation with resonance from benzene ring → **moderately stable** - **I (Cycloheptatrienyl)**: Non-aromatic, allylic but less resonance stabilization → **least stable** **Step 4: Verify order** $$\text{III} > \text{II} > \text{IV} > \text{I}$$ This matches **option (D)**.