Alkyl chloride is formed when alcohol is treated with HCl in presence of anhydrous `ZnCl_(2)`. The order of reactivity with respect to alcohol is

Options

A. `3^(@) gt 2^(@) gt 1^(@)`
B. `1^(@) gt 2^(@) gt 3^(@)`
C. `2^(@) gt 1^@ gt 3^(@)`
D. `1^(@) gt 3^@ gt 2^(@)`

Explanation

To determine the order of reactivity of alcohols when treated with HCl in the presence of anhydrous ZnCl₂, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**:
- When alcohol (ROH) is treated with hydrochloric acid (HCl) in the presence of anhydrous zinc chloride (ZnCl₂), an alkyl chloride is formed. This reaction is known as the Lucas test.

2. **Understand the Role of Lucas Reagent**:
- The combination of HCl and anhydrous ZnCl₂ is referred to as Lucas reagent. It is used to differentiate between primary, secondary, and tertiary alcohols based on their reactivity.

3. **Reactivity of Alcohols**:
- Tertiary alcohols (3°) react the fastest with Lucas reagent, resulting in immediate turbidity (cloudiness) due to the formation of alkyl chloride.
- Secondary alcohols (2°) show turbidity after a few minutes (typically 5 to 10 minutes).
- Primary alcohols (1°) do not react significantly with Lucas reagent and do not show turbidity.

4. **Order of Reactivity**:
- Based on the observations from the Lucas test, the order of reactivity of alcohols can be established as follows:
- Tertiary alcohols (3°) > Secondary alcohols (2°) > Primary alcohols (1°).

5. **Conclusion**:
- Therefore, the order of reactivity with respect to alcohols when treated with HCl in the presence of anhydrous ZnCl₂ is:
- **Tertiary > Secondary > Primary**.

### Final Answer:
The order of reactivity of alcohols with respect to the formation of alkyl chloride when treated with HCl in the presence of anhydrous ZnCl₂ is:
**Tertiary > Secondary > Primary**.

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