`1^(@)` alcohols preferably undergo dehydration via

Options

A. `E_(1)`
B. `E_(2)`
C. `S_(N)1`
D. `S_(N)2`

Explanation

### Step-by-Step Solution:

1. **Identify the Type of Alcohol**:
- The question specifies "1° alcohol" (primary alcohol). An example of a primary alcohol is ethanol (CH3CH2OH).

2. **Understand the Dehydration Process**:
- Dehydration of alcohols involves the elimination of water (H2O) from the alcohol molecule, leading to the formation of alkenes.

3. **Reaction with Acid**:
- When a primary alcohol reacts with a strong acid like dilute sulfuric acid (H2SO4), the alcohol undergoes protonation. The hydroxyl group (OH) of the alcohol accepts a proton (H+) from the acid, forming an alkyl oxonium ion (CH3CH2OH2+).

4. **Formation of Carbocation**:
- The alkyl oxonium ion is unstable and will lose a water molecule (H2O), leading to the formation of a carbocation (CH3CH2+). This step is crucial as it indicates the formation of a reactive intermediate.

5. **Elimination of Proton**:
- In the presence of a base, a proton (H+) is removed from the adjacent carbon atom of the carbocation, resulting in the formation of a double bond. This step leads to the formation of an alkene (CH2=CH2).

6. **Mechanism Type**:
- The dehydration of primary alcohols typically follows the E2 mechanism rather than E1 because E1 mechanisms are more common with tertiary alcohols due to the stability of the carbocation formed. In the case of primary alcohols, the elimination occurs in a concerted manner (E2).

7. **Conclusion**:
- Therefore, the preferred mechanism for the dehydration of 1° alcohols is the E2 mechanism.

### Final Answer:
1° alcohols preferably undergo dehydration via **E2 mechanism**.

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