Tertiary butyl alcohol gives tertiary butyl chloride on treatement with

Options

A. conc. HCl / anhydrous `ZnCl_(2)`
B. KCN
C. NaOCl
D. `Cl_(2)`

Explanation

To solve the question "Tertiary butyl alcohol gives tertiary butyl chloride on treatment with?", we will follow these steps:

### Step 1: Identify Tertiary Butyl Alcohol
Tertiary butyl alcohol (also known as 2-methylpropan-2-ol) has the structure:
\[ \text{(CH}_3)_3\text{COH} \]
This means it has three methyl groups attached to a central carbon atom that is also bonded to a hydroxyl (OH) group.

### Step 2: Determine the Reagent Required
To convert tertiary butyl alcohol to tertiary butyl chloride, we need a reagent that can facilitate this transformation. The most suitable reagent for this reaction is concentrated hydrochloric acid (HCl) in the presence of zinc chloride (ZnCl2), which is known as Lucas reagent.

### Step 3: Reaction Mechanism
1. **Formation of the Alkyl Chloride**: The hydroxyl group (OH) of tertiary butyl alcohol is protonated by the acid (HCl), converting it into a better leaving group (water).
2. **Carbocation Formation**: The protonation leads to the formation of a carbocation intermediate, which is stabilized due to the tertiary structure.
3. **Nucleophilic Attack**: The chloride ion (Cl-) from HCl then attacks the carbocation, resulting in the formation of tertiary butyl chloride.

### Step 4: Write the Final Reaction
The overall reaction can be summarized as:
\[ \text{(CH}_3)_3\text{COH} + \text{HCl} \xrightarrow{\text{ZnCl}_2} \text{(CH}_3)_3\text{CCl} + \text{H}_2\text{O} \]

### Conclusion
Thus, tertiary butyl alcohol gives tertiary butyl chloride on treatment with concentrated HCl and ZnCl2 (Lukas reagent).