Neopentyl alcohol on treatment with HCl and anhydrous `ZnCl_(2)` gives

Options

A. 2-Chloro-3-methylbutane
B. 2-Chloro-2-methylbutane
C. 1-Chloro-2,2-dimethylpropane
D. None of these

Explanation

To solve the problem of what product is formed when neopentyl alcohol is treated with HCl and anhydrous ZnCl₂, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of Neopentyl Alcohol**:
- Neopentyl alcohol is a branched alcohol with the formula \(C_5H_{12}O\). Its structure can be represented as:
\[ \text{CH}_3-\text{C}(\text{CH}_3)_2-\text{CH}_2-\text{OH} \]
- This shows that the hydroxyl group (-OH) is attached to a carbon that is also connected to two other methyl groups.

2. **Reaction with HCl**:
- When neopentyl alcohol reacts with HCl, the hydroxyl group (-OH) is protonated, making it a better leaving group. This leads to the formation of a carbocation after the loss of water (H₂O) and chloride ion (Cl⁻):
\[ \text{CH}_3-\text{C}(\text{CH}_3)_2-\text{CH}_2^+ \]
- The carbocation formed here is a primary carbocation (1°) because it is attached to only one alkyl group.

3. **Carbocation Rearrangement**:
- Primary carbocations are not stable. To stabilize the carbocation, a methyl shift occurs. This means that one of the methyl groups from the adjacent carbon shifts to the carbocation carbon, resulting in a more stable tertiary carbocation:
\[ \text{CH}_3-\text{C}^+(\text{CH}_3)-\text{CH}_2-\text{CH}_3 \]
- This new carbocation is now a tertiary carbocation (3°) and is more stable.

4. **Nucleophilic Attack by Cl⁻**:
- The chloride ion (Cl⁻) acts as a nucleophile and attacks the positively charged carbon of the tertiary carbocation, leading to the formation of the final product:
\[ \text{CH}_3-\text{C}(\text{Cl})(\text{CH}_3)-\text{CH}_2-\text{CH}_3 \]
- This compound is 2-chloro-2-methylbutane.

5. **Final Product**:
- The final product of the reaction is identified as:
\[ \text{2-chloro-2-methylbutane} \]

### Conclusion:
The product formed when neopentyl alcohol is treated with HCl and anhydrous ZnCl₂ is **2-chloro-2-methylbutane**.