The reagent used for Friedel-Craft's reaction is :

Options

A. Dry ether
B. `AlCl_3`
C. Anhydrous `AlCl_3`
D. `P_2O_5`

Answer

To answer the question regarding the reagent used for Friedel-Craft's reaction, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding Friedel-Craft's Reaction**:
- Friedel-Craft's reaction is a type of electrophilic aromatic substitution where an alkyl group is introduced into an aromatic ring (like benzene).

2. **Identifying the Reagents**:
- The reaction typically involves benzene and an alkyl halide (like methyl chloride or ethyl chloride).
- A catalyst is required to facilitate the reaction, which is usually an aluminum chloride (AlCl3).

3. **Role of Aluminum Chloride**:
- In the presence of anhydrous aluminum chloride (AlCl3), the alkyl halide reacts to generate a carbocation (an electrophile).
- For example, when methyl chloride (CH3Cl) reacts with AlCl3, it forms a methyl cation (CH3+) and AlCl4-.

4. **Electrophilic Attack**:
- The generated carbocation (CH3+) then attacks the benzene ring, substituting one of the hydrogen atoms and forming an alkyl-substituted benzene (like toluene).

5. **Final Product**:
- The overall reaction results in the formation of an alkyl benzene and a hydrogen halide (HCl in the case of methyl chloride).

6. **Conclusion**:
- Therefore, the reagent used for Friedel-Craft's reaction is anhydrous aluminum chloride (AlCl3).

### Final Answer:
The reagent used for Friedel-Craft's reaction is **anhydrous AlCl3**.

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