Preparation of diethyl ether by dehydration of alcohol is an:

Options

A. `SN^(1)` reaction
B. `SN^(2)` reaction
C. Nucleophilic addition reaction
D. Elimination reaction

Explanation

**Step-by-Step Solution:**

1. **Identify the Reaction Type**: The dehydration of alcohol to form diethyl ether is a type of chemical reaction. We need to classify this reaction correctly.

2. **Understand the Reactants**: The reactant in this case is ethyl alcohol (ethanol, C2H5OH). We will be dehydrating this alcohol to form diethyl ether (C2H5OC2H5).

3. **Reaction Conditions**: The reaction typically requires acidic conditions, often using concentrated sulfuric acid (H2SO4) as a catalyst, and is carried out at elevated temperatures (around 413 K).

4. **Mechanism of the Reaction**:
- The first step involves protonation of the alcohol (ethanol) by the acid, forming an ethyl oxonium ion (C2H5OH2+).
- This oxonium ion is then susceptible to nucleophilic attack by another molecule of ethanol.

5. **Formation of Carbocation**: The protonated alcohol loses a water molecule (H2O), leading to the formation of a carbocation (C2H5+).

6. **Nucleophilic Attack**: The nucleophilic attack occurs when another ethyl alcohol molecule attacks the carbocation, leading to the formation of diethyl ether.

7. **Final Product**: The final product of this reaction is diethyl ether (C2H5OC2H5), and the overall reaction can be summarized as:
\[ 2 \text{C}_2\text{H}_5\text{OH} \xrightarrow{\text{H}_2\text{SO}_4, 413 \text{K}} \text{C}_2\text{H}_5\text{O}\text{C}_2\text{H}_5 + \text{H}_2\text{O} \]

8. **Conclusion**: Based on the mechanism and the steps involved, we conclude that the dehydration of alcohol to form diethyl ether is a **nucleophilic substitution reaction**.

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