An acyl halide is formed when `PCl_(5)` reacts with an

Options

A. Acid
B. Alcohol
C. Amide
D. Ester

Explanation

To solve the question regarding the formation of an acyl halide when PCl₅ reacts with an acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- We are given PCl₅ (phosphorus pentachloride) as one reactant.
- The other reactant is an acid, which is typically a carboxylic acid.

2. **Understanding Acyl Halides**:
- Acyl halides are derivatives of carboxylic acids where the hydroxyl group (-OH) is replaced by a halogen (in this case, chlorine).
- The general formula for acyl halides is RCOX, where R is an alkyl or aryl group and X is a halogen.

3. **Reaction with PCl₅**:
- When a carboxylic acid reacts with PCl₅, it converts the -OH group of the acid into a -Cl group, thus forming an acyl chloride (acyl halide).
- The reaction can be represented as:
\[ RCOOH + PCl_5 \rightarrow RCOCl + POCl_3 + HCl \]
- Here, RCOOH is the carboxylic acid, and RCOCl is the acyl chloride formed.

4. **Example**:
- If we take acetic acid (CH₃COOH) as an example:
\[ CH_3COOH + PCl_5 \rightarrow CH_3COCl + POCl_3 + HCl \]
- This shows that acetic acid reacts with PCl₅ to form acetyl chloride (an acyl halide).

5. **Conclusion**:
- Therefore, when PCl₅ reacts with a carboxylic acid, an acyl halide is formed.