`P overset(H_2 //Pd - BaSO_4) to Q underset((ii) d I l HCI ) overset((i) "conc " NaHO ) to R+S `
Rand S form benzyl benzoate when treated with each other. Hence, `P`is

Options

A. `C_6H_5 CHO`
B. `C_6H_5CH_2OH`
C. `C_6 H_5COCI`
D. `C_6 H_5COOH`

Explanation

To solve the problem step by step, we need to analyze the reactions and identify the compounds involved.

### Step 1: Identify the reaction involving P to Q
The first part of the reaction is given as:
\[ P \overset{H_2/Pd - BaSO_4}{\rightarrow} Q \]

Here, \( H_2/Pd - BaSO_4 \) is a catalyst used in the Rosenmund reduction, which is typically used to convert acyl chlorides to aldehydes.

### Step 2: Determine the structure of Q
Since we know that the product Q is formed from P through the Rosenmund reduction, we can conclude that:
- \( Q \) is likely to be benzaldehyde (C₆H₅CHO).

### Step 3: Identify the reaction involving Q to R + S
The next part of the reaction is:
\[ Q \overset{(i) \text{conc. } NaOH}{\rightarrow} R + S \]
\[ R + S \overset{(ii) \text{dil. } HCl}{\rightarrow} \text{Benzyl Benzoate} \]

The reaction of benzaldehyde (Q) with concentrated NaOH indicates that a self-disproportionation reaction is occurring, known as the Cannizzaro reaction. This reaction will yield:
- \( R \) as phenol (C₆H₅OH)
- \( S \) as sodium benzoate (C₆H₅COONa)

### Step 4: Confirm the formation of Benzyl Benzoate
When phenol (R) and sodium benzoate (S) react together, they form benzyl benzoate (C₆H₅COOC₆H₅). This confirms that the products R and S indeed lead to the formation of benzyl benzoate.

### Step 5: Identify P
Since we have established that:
- \( Q \) is benzaldehyde,
- and \( P \) must be the acyl chloride that yields benzaldehyde upon reduction,

We can conclude that:
- \( P \) is benzoyl chloride (C₆H₅COCl).

### Final Answer
Thus, the compound \( P \) is **benzoyl chloride** (C₆H₅COCl).

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