The compound that undergoes dehydration most readily is

Options

A. Ethyl alcohol
B. 2-methylpropan-2-ol
C. 3-methyl-2-butanol
D. Propyl alcohol

Explanation

To determine which compound undergoes dehydration most readily, we need to analyze the stability of the carbocations formed during the dehydration process of the given alcohols. The stability of carbocations is crucial because the more stable the carbocation, the more readily the dehydration reaction will occur.

### Step-by-Step Solution:

1. **Identify the Alcohols**: We are given several alcohols. Let's denote them as:
- A: Ethyl alcohol (CH3CH2OH)
- B: 2-Methylpropane-2-ol (tert-butanol)
- C: 3-Methyl-2-butanol
- D: Propyl alcohol (CH3CH2CH2OH)

2. **Understand Dehydration Mechanism**: The dehydration of alcohols typically involves:
- Protonation of the alcohol (adding H⁺ to the OH group).
- Loss of water (H₂O) to form a carbocation.
- Deprotonation to form an alkene.

3. **Analyze Each Alcohol**:
- **A: Ethyl alcohol (CH3CH2OH)**:
- Protonation leads to CH3CH2OH₂⁺.
- Loss of water gives CH3CH2⁺ (a primary carbocation).
- Primary carbocations are the least stable.

- **B: 2-Methylpropane-2-ol (tert-butanol)**:
- Protonation leads to a tertiary carbocation (CH3)₃C⁺.
- Tertiary carbocations are the most stable.
- This will undergo dehydration readily.

- **C: 3-Methyl-2-butanol**:
- Protonation leads to a secondary carbocation.
- Secondary carbocations are more stable than primary but less stable than tertiary.
- This will undergo dehydration but not as readily as tert-butanol.

- **D: Propyl alcohol (CH3CH2CH2OH)**:
- Protonation leads to CH3CH2CH2OH₂⁺.
- Loss of water gives CH3CH2CH₂⁺ (a primary carbocation).
- Similar to ethyl alcohol, this is also the least stable.

4. **Determine the Most Readily Dehydrating Compound**:
- Comparing the stability of the carbocations:
- Tertiary (2-Methylpropane-2-ol) > Secondary (3-Methyl-2-butanol) > Primary (Ethyl alcohol and Propyl alcohol).
- Therefore, **2-Methylpropane-2-ol** (option B) undergoes dehydration most readily due to the formation of a stable tertiary carbocation.

### Final Answer:
The compound that undergoes dehydration most readily is **2-Methylpropane-2-ol**.

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