The compound that reacts fastest with Lucas reagent at room temperature is

Options

A. butan-1-ol
B. butan-2-ol
C. 2-methylpropan-1-ol
D. 2-methylpropan-2-ol

Explanation

To determine which compound reacts fastest with Lucas reagent at room temperature, we need to analyze the given options based on their classification as primary, secondary, or tertiary alcohols. The reactivity of alcohols with Lucas reagent follows a specific order: tertiary alcohols react the fastest, followed by secondary alcohols, and then primary alcohols.

### Step-by-Step Solution:

1. **Understand Lucas Reagent**:
- Lucas reagent is a mixture of hydrochloric acid (HCl) and zinc chloride (ZnCl2). It is used to test the reactivity of alcohols by converting them into alkyl halides.

2. **Know the Reactivity Order**:
- The order of reactivity of alcohols with Lucas reagent is:
- Tertiary alcohols > Secondary alcohols > Primary alcohols
- Tertiary alcohols react quickly and produce turbidity immediately, secondary alcohols react within a few minutes, and primary alcohols require heating to react.

3. **Identify the Alcohols in the Options**:
- **Option A: Butane-1-ol** (CH3-CH2-CH2-CH2OH) - This is a primary alcohol.
- **Option B: Butane-2-ol** (CH3-CH(OH)-CH2-CH3) - This is a secondary alcohol.
- **Option C: 2-Methylpropane-1-ol** (CH3-CH(CH3)-CH2OH) - This is also a primary alcohol.
- **Option D: 2-Methylpropane-2-ol** (CH3-C(OH)(CH3)-CH3) - This is a tertiary alcohol.

4. **Determine the Fastest Reacting Alcohol**:
- Since we are looking for the compound that reacts fastest with Lucas reagent at room temperature, we need to identify the tertiary alcohol from the options.
- Option D (2-Methylpropane-2-ol) is the only tertiary alcohol among the options.

5. **Conclusion**:
- Therefore, the compound that reacts fastest with Lucas reagent at room temperature is **2-Methylpropane-2-ol** (Option D).

### Final Answer:
The compound that reacts fastest with Lucas reagent at room temperature is **2-Methylpropane-2-ol**.