Butane can be prepared from ethyl chloride using the following synthesis
`CH_(3)CH_(2)Cloverset((i)Li)underset((i)Cu l)rarr(CH_(3)CH_(2))_(2)LiCu overset(CH_(3)CH_(2)Cl)rarr CH_(3)CH_(2)CH_(2)CH_(3)`
The reaction is

Options

A. Wurtz reaction
B. Kolbe's electrolytic method
C. Sandmayer's reaction
D. Corey - House synthesis

Answer

To determine the type of reaction that converts ethyl chloride into butane using lithium and copper lithium, we can analyze the steps involved in the synthesis.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The starting material is ethyl chloride (CH₃CH₂Cl).
- The final product is butane (CH₃CH₂CH₂CH₃).

2. **First Reaction**:
- The first step involves treating ethyl chloride with lithium (Li) in the presence of copper lithium (LiCu).
- This step generates a lithium dialkylcuprate, specifically (CH₃CH₂)₂LiCu.

3. **Formation of Lithium Dialkylcuprate**:
- The reaction can be represented as:
\[ 2 \text{CH}_3\text{CH}_2\text{Cl} + \text{Li} + \text{CuLi} \rightarrow (CH_3CH_2)_2LiCu + 2 \text{LiCl} \]
- Here, two moles of ethyl chloride react with lithium to form a lithium dialkylcuprate.

4. **Second Reaction**:
- The lithium dialkylcuprate then reacts with another molecule of ethyl chloride:
\[ (CH_3CH_2)_2LiCu + \text{CH}_3\text{CH}_2\text{Cl} \rightarrow \text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_3 + \text{LiCl} + \text{CuCl} \]
- This step leads to the formation of butane (C₄H₁₀).

5. **Conclusion**:
- The overall reaction can be summarized as a coupling reaction where two ethyl groups are combined to form butane.
- This reaction is known as the **Corey-House synthesis**.

### Final Answer:
The reaction is the **Corey-House synthesis**.