When benzene is heated with acetic anhydride in presence of anhydrous `AlCl_(3)`, is product formed is-

Options

A. Benzoin acid
B. Acetophenone
C. Ethylphenyl ketone
D. Benzophenone

Answer

To determine the product formed when benzene is heated with acetic anhydride in the presence of anhydrous AlCl3, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this reaction are benzene (C6H6) and acetic anhydride ((CH3CO)2O). Anhydrous AlCl3 acts as a catalyst.

2. **Understand the Reaction Type**:
- This reaction is an example of an electrophilic aromatic substitution (EAS) reaction. In this case, acetic anhydride will introduce an acetyl group (CH3CO) into the benzene ring.

3. **Formation of the Electrophile**:
- In the presence of AlCl3, acetic anhydride forms an electrophile. The AlCl3 coordinates with the carbonyl oxygen of acetic anhydride, making the carbonyl carbon more electrophilic. The reaction can be represented as:
\[ (CH3CO)2O + AlCl3 \rightarrow CH3C^+=O + AlCl4^- \]
- Here, CH3C^+=O is the electrophile that will react with benzene.

4. **Electrophilic Attack**:
- The benzene ring, being rich in electrons, attacks the electrophile (CH3C^+=O), leading to the formation of a sigma complex (also known as an arenium ion).

5. **Deprotonation**:
- The sigma complex loses a proton (H+) to restore aromaticity. This step is facilitated by the presence of AlCl4^-, which can abstract the proton.

6. **Final Product**:
- The final product of this reaction is acetophenone (C6H5COCH3), which is a ketone where the acetyl group is attached to the benzene ring.

### Summary of the Reaction:
The overall reaction can be summarized as:
\[ C6H6 + (CH3CO)2O \xrightarrow{AlCl3} C6H5COCH3 + CH3COOH \]

### Final Answer:
The product formed is **acetophenone (C6H5COCH3)**.

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