What is the function of anhydrous `ZnCl_(2)` in Luca's test ?

Explanation

### Step-by-Step Solution:

1. **Understanding Lucas Test**: The Lucas test is a qualitative test used to differentiate between primary, secondary, and tertiary alcohols based on their reactivity with Lucas reagent, which is a mixture of hydrochloric acid (HCl) and anhydrous zinc chloride (ZnCl2).

2. **Role of Anhydrous ZnCl2**: Anhydrous ZnCl2 acts as a catalyst in the Lucas test. It helps in the formation of the reactive species that can react with alcohols.

3. **Reaction Mechanism**:
- When alcohol is treated with HCl in the presence of ZnCl2, the ZnCl2 reacts with HCl to form a complex, which is ZnCl4^2-.
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