`C_(6)H_(5)CH_(3) overset(CrO_(2)Cl_(2))underset(CS_(2))(rarr) A overset(H_(2)O)(rarr) B`
The functional group present in B and name of the reaction would be

Options

A. `–CHO`, Gattermann aldehyde synthesis
B. `–CHO`, Etard reaction
C. `–COCH_(3)`, Fridel Crafts reaction
D. `–CHO`, Oxo reaction

Answer

To solve the question, we will follow these steps:

### Step 1: Identify the starting compound
The starting compound is Toluene, which has the molecular formula \( C_6H_5CH_3 \). This compound consists of a benzene ring with a methyl group attached.

### Step 2: Reaction with \( CrO_2Cl_2 \)
When Toluene reacts with \( CrO_2Cl_2 \) in carbon disulfide (\( CS_2 \)), it undergoes an oxidation reaction. The methyl group (\(-CH_3\)) is oxidized to a carbonyl group (\(C=O\)), leading to the formation of a compound known as benzaldehyde.

The reaction can be summarized as follows:
\[ C_6H_5CH_3 \xrightarrow{CrO_2Cl_2} C_6H_5CHO \]
Here, \( A \) is the product formed after the oxidation, which is benzaldehyde (\( C_6H_5CHO \)).

### Step 3: Hydrolysis of \( A \)
Next, the compound \( A \) (benzaldehyde) undergoes hydrolysis in the presence of water. However, since benzaldehyde is already an aldehyde, it does not change further upon hydrolysis. Therefore, the product \( B \) remains benzaldehyde.

### Step 4: Identify the functional group in \( B \)
The functional group present in \( B \) is the aldehyde group (\(-CHO\)).

### Step 5: Name the reaction
The reaction that converts Toluene to benzaldehyde is known as the **Ettard reaction**.

### Final Answer
- The functional group present in \( B \) is the aldehyde group (\(-CHO\)).
- The name of the reaction is the **Ettard reaction**.

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