`C_(6)H_(6) +A overset(AlCl_(3))(rarr) C_(6)H_(5)CONH_(2)`
A in the above reaction is :

Options

A. `NH_(2)CONH_(2)`
B. `ClCONH_(2)`
C. `CH_(3)CONH_(2)`
D. ` CH_(2)(Cl)CONH_(2)`

Answer

To solve the question, we need to identify the compound A that reacts with benzene (C₆H₆) in the presence of aluminum chloride (AlCl₃) to produce an amide (C₆H₅CONH₂). This process is indicative of a Friedel-Crafts acylation reaction.

### Step-by-step Solution:

1. **Identify the Reaction Type**:
The reaction involves benzene and a compound A in the presence of AlCl₃. This suggests that we are dealing with a Friedel-Crafts acylation reaction, which typically introduces an acyl group (C=O) into the aromatic ring.

**Hint**: Recall that Friedel-Crafts reactions involve the formation of an electrophile that reacts with the aromatic compound.

2. **Determine the Product**:
The product of the reaction is C₆H₅CONH₂, which indicates that the acyl group is attached to the benzene ring and is followed by an amine group (NH₂). This suggests that the acyl group must be derived from an amide.

**Hint**: Focus on the functional groups present in the product to deduce the structure of compound A.

3. **Identify Compound A**:
For the reaction to yield an amide, compound A must be an acyl chloride, specifically an acyl chloride that can provide the amide functional group upon reaction. The most likely candidate is acetyl chloride (CH₃COCl), which can provide the acyl group (C=O) and can react with ammonia (NH₃) to form the amide.

**Hint**: Consider common acyl chlorides that could react in this manner.

4. **Write the Reaction**:
The reaction can be summarized as follows:
\[ C_6H_6 + CH_3COCl \overset{AlCl_3}{\rightarrow} C_6H_5COCl + HCl \]
Then, the acyl chloride can react with ammonia (NH₃) to form the amide:
\[ C_6H_5COCl + NH_3 \rightarrow C_6H_5CONH_2 + HCl \]

**Hint**: Remember that the presence of AlCl₃ is crucial for generating the electrophile from the acyl chloride.

5. **Conclusion**:
Therefore, the compound A in the reaction is acetyl chloride (CH₃COCl).

**Final Answer**: A is acetyl chloride (CH₃COCl).