The reaction
`CH_(3) COOH + Cl_(2) overset (red P) to CICH_(2) COOH + HCl` is called

Options

A. Hell-Volhard-Zelinsky reaction
B. Birch reaction
C. Rosenmund reaction
D. Hunsdiecker reaction

Answer

To solve the question regarding the reaction of ethanoic acid (CH₃COOH) with chlorine (Cl₂) in the presence of red phosphorus, we need to identify the name of the reaction. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The reactants are ethanoic acid (CH₃COOH) and chlorine (Cl₂).
- The products are chlorinated ethanoic acid (ClCH₂COOH) and hydrochloric acid (HCl).

2. **Understand the Role of Red Phosphorus**:
- Red phosphorus acts as a catalyst in this reaction, facilitating the substitution of an alpha hydrogen atom in the carboxylic acid with a chlorine atom.

3. **Recognize the Type of Reaction**:
- This reaction involves the substitution of an alpha hydrogen atom by a halogen (in this case, chlorine). This is characteristic of a specific type of reaction known as the Hell-Wolhard-Zelensky (HVZ) reaction.

4. **Confirm the Name of the Reaction**:
- The Hell-Wolhard-Zelensky reaction specifically describes the halogenation of carboxylic acids at the alpha position in the presence of a halogen and red phosphorus.

5. **Eliminate Other Options**:
- Other reactions mentioned (Birch reaction, Rosenmund's reaction, and Hundt-Sticker reaction) do not involve the halogenation of carboxylic acids in the same manner and can be eliminated.

6. **Conclude the Answer**:
- Therefore, the reaction `CH₃COOH + Cl₂ (red P) → ClCH₂COOH + HCl` is called the **Hell-Wolhard-Zelensky reaction**.

### Final Answer:
The reaction is called the **Hell-Wolhard-Zelensky reaction**.

---