Question

Which of the following reagents gives the same reduction product with propionaldehyde and acetone ?

• A. \(\text{LiAlH}_{4}\)
• B. \(\text{Ni}\ /\ \text{H}_{2}\)
• C. \(\text{Na-Hg}\ /\ \text{HCl}\)
• D. \(\text{Zn-Hg}\ /\ \text{Conc HCl}\)

Hint:

Clemmensen reduction converts both C=O groups to CH2, giving propane for both compounds.

Answer 1

The Correct Option is D

Step 1: Think about the products
To get the same product from an aldehyde and a ketone, the carbonyl must lose its oxygen completely.

Step 2: Pick the full reduction
Only Clemmensen reduction (Zn-Hg, conc. HCl) turns C=O into $\text{CH}_{2}$.

Step 3: Check the rest
The other reagents give alcohols, which are different: propan-1-ol versus propan-2-ol.

Final Answer:
Only Zn-Hg/conc. HCl removes the oxygen and gives propane in both cases. \[ \boxed{\text{(D) }\text{Zn-Hg / Conc HCl}} \]