Which of the following reagent will not be able to produce acetyl chloride by its reaction with acetic acid?

Options

A. `PCl_(5)`
B. `SOCl_(2)//Py`
C. `PCl_(3)`
D. `Cl_(2)`

Answer

To determine which reagent will not produce acetyl chloride when reacted with acetic acid, we need to analyze the reactions of acetic acid with the given reagents.

### Step-by-Step Solution:

1. **Identify Acetic Acid**:
- Acetic acid is represented as CH₃COOH. It contains a carboxylic acid functional group.

2. **Reagents to Consider**:
- The question mentions several reagents. We will analyze each one to see if it can convert acetic acid to acetyl chloride (CH₃COCl).

3. **Reaction with PCl₅**:
- When acetic acid reacts with phosphorus pentachloride (PCl₅), it produces acetyl chloride and phosphorus oxychloride (POCl₃).
- Reaction:
\[ CH₃COOH + PCl₅ \rightarrow CH₃COCl + POCl₃ \]
- **Conclusion**: PCl₅ can produce acetyl chloride.

4. **Reaction with PCl₃**:
- When acetic acid reacts with phosphorus trichloride (PCl₃), it also produces acetyl chloride.
- Reaction:
\[ CH₃COOH + PCl₃ \rightarrow CH₃COCl + HCl \]
- **Conclusion**: PCl₃ can produce acetyl chloride.

5. **Reaction with Cl₂**:
- When acetic acid reacts with chlorine gas (Cl₂), it does not directly produce acetyl chloride. Instead, it can lead to chlorination of the methyl group or other side reactions.
- **Conclusion**: Cl₂ does not produce acetyl chloride.

6. **Final Analysis**:
- Based on the reactions analyzed:
- PCl₅ → Produces acetyl chloride.
- PCl₃ → Produces acetyl chloride.
- Cl₂ → Does not produce acetyl chloride.
- Therefore, the reagent that will not produce acetyl chloride when reacted with acetic acid is Cl₂.

### Answer:
The reagent that will not be able to produce acetyl chloride by its reaction with acetic acid is **Cl₂**.

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