JEE Chemistry 2025 Question with Solution

Given: We must identify the reactions that are undergone by both acetaldehyde and acetone.

Find: The correct option containing only those reactions common to both compounds.

Analyze each reaction:

A. Iodoform Reaction: Acetaldehyde $CH_3CHO$ gives the iodoform reaction. Acetone $CH_3COCH_3$ also gives the iodoform reaction. Therefore, A is common to both.

B. Cannizzaro Reaction: Cannizzaro reaction is shown by aldehydes without $\alpha$-hydrogen. Acetaldehyde has $\alpha$-hydrogen, so it does not undergo Cannizzaro reaction. Acetone is a ketone and also does not undergo this reaction. Therefore, B is not common to both.

C. Aldol Condensation: Aldol condensation is shown by aldehydes and ketones having at least one $\alpha$-hydrogen. Both acetaldehyde and acetone have $\alpha$-hydrogen. Therefore, C is common to both.

D. Tollen's Test: Tollen's test is given by aldehydes. Acetaldehyde gives this test, but acetone does not. Therefore, D is not common to both.

E. Clemmensen Reduction: Clemmensen reduction converts aldehydes and ketones to alkanes. Both acetaldehyde and acetone undergo this reduction. Therefore, E is common to both.

So the reactions common to both are A, C and E only.

The correct option is B.

Note: The answer key points to option $A$, but the solution working clearly concludes A, C and E only, which matches option B.

Given:

• Acetaldehyde: $CH_3CHO$
• Acetone: $CH_3COCH_3$

Find: Which listed reactions are shown by both compounds.

1. Iodoform reaction requires the presence of a methyl carbonyl system. Both $CH_3CHO$ and $CH_3COCH_3$ satisfy this condition.
2. Cannizzaro reaction is not given by acetaldehyde because it has $\alpha$-hydrogen, and acetone is a ketone, so it also does not qualify.
3. Aldol condensation is given by carbonyl compounds having $\alpha$-hydrogen. Both compounds satisfy this condition.
4. Tollen's test is given by aldehydes but not ordinary ketones, so only acetaldehyde responds.
5. Clemmensen reduction is undergone by both aldehydes and ketones.

Hence the common reactions are A, C and E.

Therefore, the correct option is B.