Which of the following is an examples of Friedel Crafts reaction ?

Options

A.
B.
C.
D. All of these

Answer

To determine which of the given reactions is an example of Friedel-Crafts reactions, we need to understand what Friedel-Crafts reactions entail. There are two main types of Friedel-Crafts reactions: Friedel-Crafts alkylation and Friedel-Crafts acylation.

### Step-by-Step Solution:

1. **Understanding Friedel-Crafts Reactions**:
- Friedel-Crafts reactions involve the introduction of an alkyl or acyl group into an aromatic ring (like benzene) using a Lewis acid as a catalyst.
- The Lewis acid helps generate an electrophile that can react with the π electrons of the aromatic ring.

2. **Identifying the Reagents**:
- In the case of Friedel-Crafts alkylation, an alkyl halide (like CH3Cl) is used along with a Lewis acid (like AlCl3).
- For Friedel-Crafts acylation, an acyl halide (like RCOCl) is used, also with a Lewis acid.

3. **Analyzing the Given Options**:
- If one of the options includes CH3Cl with AlCl3, it represents Friedel-Crafts alkylation.
- If another option includes an acyl chloride (like C=O with Cl) with AlCl3, it represents Friedel-Crafts acylation.

4. **Reaction Mechanism**:
- For alkylation: The alkyl halide reacts with the Lewis acid to form a carbocation (electrophile), which then attacks the aromatic ring, resulting in the substitution of a hydrogen atom.
- For acylation: The acyl halide forms an acylium ion (electrophile) with the help of the Lewis acid, which then reacts with the aromatic ring.

5. **Conclusion**:
- All reactions that involve the generation of an electrophile from an alkyl or acyl halide in the presence of a Lewis acid and the subsequent substitution on an aromatic ring are classified as Friedel-Crafts reactions.

### Final Answer:
All of the reactions listed in the options are examples of Friedel-Crafts reactions, including both alkylation and acylation.