Why is the reactivity of all the three classes of alcohols with conc. HCl and `ZnCl_(2)` (Lucas reagent) different ?

Explanation

To understand why the reactivity of the three classes of alcohols (primary, secondary, and tertiary) with concentrated HCl and ZnCl₂ (Lucas reagent) is different, we need to analyze the stability of the carbocations formed during the reaction. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understanding the Reaction with Lucas Reagent
When an alcohol reacts with Lucas reagent (HCl and ZnCl₂), the alcohol undergoes a substitution reaction where the hydroxyl (-OH) group is replaced by a chloride (-Cl) ion. The first step involves the formation of a carbocation after the -OH group leaves.

### Step 2: Carbocation Formation
The stability of the carbocation formed during the reaction is crucial. The three classes of alcohols yield different carbocations:
- **Primary Alcohols** (1°): Form a primary carbocation (R-CH₂⁺), which is less stable.
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