Q143 / 200 · MHT CET - Medical 2026 (21 April Shift 2) · Chemistry
Which of the following compounds will not undergo aldol condensation?
- A$\text{CH}_3\text{-CHO}$ (Acetaldehyde)
- B$\text{CH}_3\text{-CO-CH}_3$ (Acetone)
- Correct answerC$\text{C}_6\text{H}_5\text{-CHO}$ (Benzaldehyde)
- D$\text{CH}_3\text{-CH}_2\text{-CHO}$ (Propionaldehyde)
Solution
Aldol condensation is given by aldehydes and ketones containing at least one $\alpha$-hydrogen atom.
Acetaldehyde ($\text{CH}_3\text{-CHO}$) has three $\alpha$-hydrogen atoms.
Acetone ($\text{CH}_3\text{-CO-CH}_3$) has six $\alpha$-hydrogen atoms.
Propionaldehyde ($\text{CH}_3\text{-CH}_2\text{-CHO}$) has two $\alpha$-hydrogen atoms.
Benzaldehyde ($\text{C}_6\text{H}_5\text{-CHO}$) does not have any $\alpha$-hydrogen atom.
Therefore, benzaldehyde will not undergo aldol condensation.
Answer: $\text{C}_6\text{H}_5\text{-CHO}$ (Benzaldehyde)
Acetaldehyde ($\text{CH}_3\text{-CHO}$) has three $\alpha$-hydrogen atoms.
Acetone ($\text{CH}_3\text{-CO-CH}_3$) has six $\alpha$-hydrogen atoms.
Propionaldehyde ($\text{CH}_3\text{-CH}_2\text{-CHO}$) has two $\alpha$-hydrogen atoms.
Benzaldehyde ($\text{C}_6\text{H}_5\text{-CHO}$) does not have any $\alpha$-hydrogen atom.
Therefore, benzaldehyde will not undergo aldol condensation.
Answer: $\text{C}_6\text{H}_5\text{-CHO}$ (Benzaldehyde)
Hence, the correct answer is option: 'C'.