JEE Chemistry 2024 Question with Solution

Given: The problem shows a specific chemical reaction and asks for its name.

Find: Identify the named reduction reaction.

The solution states that the reaction is the reduction of an acyl chloride to an aldehyde using hydrogen gas and poisoned palladium catalyst.

Concept Used: Rosenmund reduction converts an acyl chloride into an aldehyde using hydrogen in the presence of $Pd/BaSO_4$.

Step 1: Identify the reactant and product shown in the solution.

• The starting material is benzoyl chloride, $C_6H_5COCl$.
• The product is benzaldehyde, $C_6H_5CHO$.

So, the transformation is from an acid chloride group to an aldehyde group.

Step 2: Identify the reagents.

• Hydrogen gas, $H_2$
• Palladium on barium sulfate, $Pd-BaSO_4$

Step 3: Match this transformation with the named reaction. The catalytic reduction of an acyl chloride to an aldehyde using $H_2$ over poisoned palladium is the hallmark of Rosenmund reduction.

The solution says "The Correct Option is D", but the detailed working in both extracted solutions clearly concludes the reaction is Rosenmund reduction. Therefore, the worked solution supports Option A from the given options.

Therefore, the correct option is A.

Given: An acid chloride is reduced to an aldehyde in the presence of $H_2$ and $Pd-BaSO_4$.

Find: The name of the reaction.

Identify the reaction components:

• Acid chloride as the starting compound
• Aldehyde as the product
• Reagents: $H_2$ and $Pd-BaSO_4$

Why this matters: In organic chemistry, this reagent combination is specifically used for controlled reduction. The poisoned catalyst decreases catalytic activity so that reduction stops at the aldehyde stage and does not continue to the alcohol.

Hence, this named reaction is Rosenmund reduction.

Therefore, the correct option is A.