Which of the following alcohols will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature ?
Thinking process
To solve this problem, students keep in mind that tertiary alcohol being most reactive react at room temperature.

Options

A. `CH_(3)CH_(2)-CH_(2)-OH`
B. `CH_(3)CH_(2)-underset(CH_(3))underset(|)"CH"-OH`
C. `CH_(3)CH_(2)-underset(CH_(3))underset(|)"CH"-OH `
D. `CH_(3)CH_(2)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)C-OH`

Explanation

To determine which alcohol will yield the corresponding alkyl chloride upon reaction with concentrated HCl at room temperature, we need to analyze the stability of the carbocations formed during the reaction. Here’s a step-by-step breakdown of the solution:

### Step-by-Step Solution:

1. **Identify the Alcohols**: List the given alcohols and their structures. We will analyze each one to see if it can form a carbocation upon reaction with concentrated HCl.

2. **Protonation of Alcohol**: When an alcohol reacts with concentrated HCl, the hydroxyl group (-OH) is protonated by HCl to form a better leaving group, water (H2O). This step generates a protonated alcohol (ROH2+).

3. **Formation of Carbocation**: The protonated alcohol then loses a water molecule, forming a carbocation (R+). The stability of this carbocation is crucial for determining whether the reaction will proceed.

4. **Stability of Carbocations**: Recall that the stability of carbocations increases in the following order:
- Primary (1°) < Secondary (2°) < Tertiary (3°)
Therefore, tertiary alcohols will form the most stable carbocations and are more likely to react at room temperature.

5. **Analyze Each Alcohol**:
- **1-Propanol (1°)**: Forms a primary carbocation, which is unstable. Reaction is unlikely.
- **2-Butanol (2°)**: Forms a secondary carbocation, which is more stable than a primary but less stable than a tertiary. Reaction can occur but is slower.
- **2-Pentanol (2°)**: Similar to 2-butanol, forms a secondary carbocation. Reaction can occur but is slower.
- **Tertiary Butanol (3°)**: Forms a tertiary carbocation, which is very stable. Reaction will occur readily at room temperature.

6. **Conclusion**: Since tertiary alcohols form the most stable carbocations and react readily with HCl, the alcohol that will yield the corresponding alkyl chloride at room temperature is **Tertiary Butanol**.

### Final Answer:
The alcohol that will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature is **Tertiary Butanol**.

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