See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Carbanion Stability via Resonance **Key Principle:** Carbanion stability increases when the negative charge is delocalized (spread out) through resonance with electron-withdrawing groups. ## Evaluation of Each Option: **(A) Benzyl carbanion ($H_2\overset{\ominus}{C}$-Ph)** - Resonance stabilization into aromatic ring - Negative charge delocalized over ortho/para positions - Good stability, but not the best **(B) Carbanion adjacent to ester ($H_2\overset{\ominus}{C}$-CO₂Me)** - Negative charge can resonate into the carbonyl - Resonance structure: $H_2C^+=C(-O^-)OMe$ - Strong stabilization via electron-withdrawing carbonyl **(C) Carbanion adjacent to ketone ($H_2\overset{\ominus}{C}$-COMe)** ✓ - Negative charge resonates into the C=O group - Resonance structure: $H_2C^+=C(-O^-)Me$ - The carbonyl group is **more electron-withdrawing** than an ester (no oxygen donation to stabilize the positive charge on C in the resonance form) - **Maximum charge delocalization** onto the highly electronegative oxygen atom - This is the **most stable** carbanion **(D) Allylic carbanion ($H_2\overset{\ominus}{C}$-CH=CH₂)** - Delocalization only over C=C π system - Weakest stabilization; negative charge remains largely on carbon ## Answer: **Option (C)** is correct because the ketone's carbonyl oxygen most effectively delocalizes the negative charge through resonance, providing maximum stabilization with oxygen bearing the bulk of the charge density.