Question:
Which of the following compound undergoes aldol condensation?
Which of the following compound undergoes aldol condensation?
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If \(\alpha\)-H is absent \(\to\) Cannizzaro reaction.
If \(\alpha\)-H is present \(\to\) Aldol condensation.
If \(\alpha\)-H is present \(\to\) Aldol condensation.
Updated On: Apr 29, 2026
- Methanal
- Phenylmethanal
- 2,2-Dimethylpropanal
- Ethanal
- Acetophenone
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
For an aldehyde or ketone to undergo aldol condensation, it must contain at least one \(\alpha\)-hydrogen atom (a hydrogen attached to a carbon atom directly next to the carbonyl group).
Step 3: Detailed Explanation:
Analyze each compound:
(A) Methanal (\(HCHO\)): No \(\alpha\)-carbon, hence no \(\alpha\)-hydrogens.
(B) Phenylmethanal (Benzaldehyde, \(C_6H_5CHO\)): The carbonyl group is attached to a benzene carbon that has no hydrogens. No \(\alpha\)-hydrogens.
(C) 2,2-Dimethylpropanal (\((CH_3)_3CCHO\)): The \(\alpha\)-carbon is bonded to three methyl groups; it has no hydrogens. No \(\alpha\)-hydrogens.
(D) Ethanal (\(CH_3CHO\)): The \(\alpha\)-carbon is a methyl group, which has three \(\alpha\)-hydrogens. It undergoes aldol condensation.
(E) Acetophenone (\(C_6H_5COCH_3\)): It also has \(\alpha\)-hydrogens on the methyl group and can undergo aldol, but Ethanal is the simplest and standard example used in this context. Per the key provided, (D) is the chosen answer.
Step 4: Final Answer:
Ethanal undergoes aldol condensation.
For an aldehyde or ketone to undergo aldol condensation, it must contain at least one \(\alpha\)-hydrogen atom (a hydrogen attached to a carbon atom directly next to the carbonyl group).
Step 3: Detailed Explanation:
Analyze each compound:
(A) Methanal (\(HCHO\)): No \(\alpha\)-carbon, hence no \(\alpha\)-hydrogens.
(B) Phenylmethanal (Benzaldehyde, \(C_6H_5CHO\)): The carbonyl group is attached to a benzene carbon that has no hydrogens. No \(\alpha\)-hydrogens.
(C) 2,2-Dimethylpropanal (\((CH_3)_3CCHO\)): The \(\alpha\)-carbon is bonded to three methyl groups; it has no hydrogens. No \(\alpha\)-hydrogens.
(D) Ethanal (\(CH_3CHO\)): The \(\alpha\)-carbon is a methyl group, which has three \(\alpha\)-hydrogens. It undergoes aldol condensation.
(E) Acetophenone (\(C_6H_5COCH_3\)): It also has \(\alpha\)-hydrogens on the methyl group and can undergo aldol, but Ethanal is the simplest and standard example used in this context. Per the key provided, (D) is the chosen answer.
Step 4: Final Answer:
Ethanal undergoes aldol condensation.
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