See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

## Analysis of Carbocation Stability **Identifying each carbocation:** - **I**: $H_2C=CH-\overset{+}{C}H_2$ — allylic (secondary) carbocation - **II**: $H_3C-CH_2-\overset{+}{C}H_2$ — primary carbocation - **III**: Benzyl carbocation ($C_6H_5-CH_2^+$) — resonance-stabilized by aromatic ring **Stability factors:** 1. **Resonance stabilization** (strongest): The benzyl carbocation (III) is stabilized by delocalization of positive charge into the aromatic π-system through resonance structures. This makes it highly stable. 2. **Hyperconjugation & alkyl substitution**: The allylic carbocation (I) has secondary character with π-bond participation, making it more stable than a simple primary carbocation. 3. **No stabilization**: Primary carbocation (II) lacks both resonance and significant hyperconjugation. **Stability order:** $$III > I > II$$ This corresponds to **option (C)**. --- **Why others are wrong:** - **(A)** Inverts the primary/secondary relationship - **(B)** Underestimates benzyl carbocation stability - **(D)** Places II above I, ignoring allylic stabilization