When benzoic acid is treated with `PCl_(5)` at `100^(@)C`, it gives

Options

A. Benzoyl chloride
B. o-chlorobenzoic acid
C. p-chlorobenzoic acid
D. Benzyl chloride

Answer

To solve the question about the reaction of benzoic acid with phosphorus pentachloride (PCl₅) at 100°C, we can follow these steps:

### Step 1: Understand the Reactants
Benzoic acid (C₇H₆O₂) is a carboxylic acid with the functional group -COOH. Phosphorus pentachloride (PCl₅) is a chlorinating agent that can convert carboxylic acids into acyl chlorides.

### Step 2: Identify the Reaction
When benzoic acid reacts with PCl₅, the -OH group of the carboxylic acid is replaced by a chlorine atom, resulting in the formation of benzoyl chloride (C₇H₅ClO).

### Step 3: Write the Chemical Equation
The reaction can be represented as follows:
\[ \text{C}_6\text{H}_5\text{COOH} + \text{PCl}_5 \rightarrow \text{C}_6\text{H}_5\text{COCl} + \text{POCl}_3 + \text{HCl} \]

### Step 4: Analyze the Products
The main product of this reaction is benzoyl chloride (C₆H₅COCl). Additionally, phosphorus oxychloride (POCl₃) and hydrochloric acid (HCl) are also formed as by-products.

### Final Answer
When benzoic acid is treated with PCl₅ at 100°C, it gives benzoyl chloride (C₆H₅COCl).

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