Toluene on reaction with `CrO_(3)` and `Ac_(2)O` gives benzaldehyde as the main product. The intermediate compound formed in the reaction is:

Options

A. a.`PhCH_(2)OH`
B. b.`PhCH(Oac)_(2)`
C. c.`PhCH_(2)Oac`
D. d.`PhCH(OH)_(2)`

Explanation

To solve the problem of identifying the intermediate compound formed when toluene reacts with CrO3 and Ac2O to yield benzaldehyde, we can follow these steps:

### Step 1: Understand the Reactants
- **Toluene** is an aromatic compound with the formula C6H5CH3, where a methyl group (–CH3) is attached to a benzene ring.
- **CrO3** (Chromium trioxide) is a strong oxidizing agent.
- **Ac2O** (Acetic anhydride) is used as a solvent and also plays a role in the reaction.

### Step 2: Identify the Reaction Type
- The reaction involves the oxidation of the methyl group in toluene to form an aldehyde. This is a typical oxidation reaction where the –CH3 group is converted to a –CHO (aldehyde) group.

### Step 3: Determine the Mechanism
- The reaction proceeds through the formation of an intermediate compound. In this case, the methyl group (–CH3) is oxidized to a carbonyl group (–C=O) while still being attached to the benzene ring.
- The presence of acetic anhydride (Ac2O) facilitates the formation of an acylated intermediate.

### Step 4: Write the Structure of the Intermediate
- The intermediate formed can be represented as follows:
- The methyl group (–CH3) is oxidized to a –CHO group, and the remaining structure is influenced by the acetic anhydride.
- The intermediate compound can be represented as:
- C6H5C(=O)OCOCH3 (where C(=O)OCOCH3 represents the acyl group from acetic anhydride).

### Step 5: Finalize the Intermediate Structure
- The final structure of the intermediate can be simplified to:
- **O=C(OCOCH3)C6H5** or **C6H5C(=O)OCOCH3**, which indicates that the intermediate has a phenyl group (C6H5), a carbonyl group (C=O), and an acyl group from acetic anhydride.

### Conclusion
- The intermediate compound formed in the reaction of toluene with CrO3 and Ac2O is **OCOCH3** (which represents the acyl group), and the entire structure can be summarized as **C6H5C(=O)OCOCH3**.

### Final Answer
The intermediate compound formed in the reaction is **OCOCH3**.