RE-NEET 2026 Chemistry Aldol Condensation MCQ Question

NCERT Topic: Aldehydes, Ketones & Carboxylic Acids → Aldol Condensation

Difficulty: 🔴 Hard

✅ Ans: 4 → D

The ketone has only one α-carbon bearing H, so enolate formation occurs only there.

In aldol condensation, dehydration gives:

$$\boxed{\alpha,\beta\text{-unsaturated carbonyl compound}}$$

For self-aldol condensation, the new $C=C$ must form between the α-carbon of one molecule and the carbonyl carbon of the other.

• A, B, C → structurally possible products ✅
• D → $C=C$ is formed at the wrong position; it does not arise from the required aldol dehydration pathway ❌

📌 NCERT line: “Aldol condensation gives α,β-unsaturated carbonyl compounds on heating.”

🧠 NEET Trick: Find α-H → form enolate → attack $C=O$ → dehydration → $C=C$ must be α,β to $C=O$.

$$\boxed{\text{Answer = D (4)}}$$