Question

Which of the following does not undergo aldol condensation?

• A. CH\(_3\)CHO
• B. CH\(_3\)COCH\(_3\)
• C. C\(_6\)H\(_5\)CHO
• D. C\(_2\)H\(_5\)CHO

Hint:

Aldehydes/ketones must have at least one \(\alpha\)-hydrogen (hydrogen on carbon adjacent to C=O) to undergo aldol condensation. Aromatic aldehydes like benzaldehyde lack it.

Answer 1

The Correct Option is C

Aldol condensation occurs in aldehydes and ketones having \(\alpha\)-hydrogen atoms. Let's analyze: - (A) CH\(_3\)CHO (Acetaldehyde): Has \(\alpha\)-hydrogens → undergoes aldol
- (B) CH\(_3\)COCH\(_3\) (Acetone): Has \(\alpha\)-hydrogens → undergoes aldol
- (C) C\(_6\)H\(_5\)CHO (Benzaldehyde): No \(\alpha\)-hydrogens → does not undergo aldol
- (D) C\(_2\)H\(_5\)CHO (Propionaldehyde): Has \(\alpha\)-hydrogens → undergoes aldol
So, only benzaldehyde cannot undergo aldol condensation. \[ \boxed{\text{C}_6\text{H}_5\text{CHO does not undergo aldol condensation}} \]