Which one of the following reaction is called Rosenmund reaction ?

Options

A. Aldehydes are reduced to alcohols
B. Acids are converted to acid chlorides
C. Alcohols are reduced to hydrocarbons
D. Acid chlorides are reduced to aldehydes

Explanation

To determine which reaction is called the Rosenmund reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Rosenmund Reaction**:
The Rosenmund reaction is a specific chemical reaction that involves the reduction of an acid chloride to an aldehyde.

2. **Identifying the Reactants and Products**:
In this reaction, the starting material is an acid chloride (R-C(=O)-Cl), and the product is an aldehyde (R-C(=O)-H).

3. **Catalyst Used**:
The reaction is typically carried out using hydrogen gas (H2) in the presence of a palladium catalyst (Pd) supported on barium sulfate (BaSO4). This catalyst helps facilitate the reduction process.

4. **Reaction Mechanism**:
During the reaction, the acid chloride reacts with hydrogen in the presence of the catalyst, leading to the cleavage of the carbon-chlorine bond and the formation of the aldehyde, along with the release of hydrochloric acid (HCl) as a byproduct.

5. **Conclusion**:
Therefore, the correct answer to the question is that the Rosenmund reaction is the reduction of acid chloride to aldehyde.

### Final Answer:
The reaction called the Rosenmund reaction is the reduction of acid chloride to aldehyde.