Which of the following alcohol will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature with fastest rate?

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-CH_(2)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 on reaction with concentrated HCl at room temperature with the fastest rate, we need to consider the stability of the carbocation that forms during the reaction. Here’s a step-by-step solution:

### Step 1: Understand the Reaction Mechanism
When an alcohol (ROH) reacts with concentrated HCl, the first step involves the protonation of the alcohol to form an oxonium ion (R-OH2^+). This is facilitated by the H^+ ion from HCl.

**Hint:** Remember that the protonation of alcohol makes it a better leaving group.

### Step 2: Formation of Carbocation
The oxonium ion (R-OH2^+) can then lose a water molecule (H2O), leading to the formation of a carbocation (R^+). The stability of this carbocation is crucial for the rate of the reaction.

**Hint:** The stability of carbocations increases in the order: primary < secondary < tertiary.

### Step 3: Identify the Type of Alcohol
Now, we need to evaluate the types of alcohols provided in the options. Identify whether they are primary, secondary, or tertiary alcohols.

**Hint:** Look for the number of carbon atoms directly attached to the carbon bearing the hydroxyl group (OH).

### Step 4: Determine Carbocation Stability
For each type of alcohol:
- **Primary alcohols** form primary carbocations, which are the least stable.
- **Secondary alcohols** form secondary carbocations, which are more stable than primary.
- **Tertiary alcohols** form tertiary carbocations, which are the most stable.

**Hint:** The more stable the carbocation, the faster the reaction will proceed.

### Step 5: Conclusion
Since tertiary carbocations are the most stable, the alcohol that will yield the corresponding alkyl chloride at the fastest rate when reacted with concentrated HCl at room temperature will be the tertiary alcohol.

**Final Answer:** The correct option is the tertiary alcohol (option D).