`2-`Hexyne gives cis `-2-` hexene on treatment with `:`

Options

A. `Li//NH_(3)`
B. `Pd//BaSO_(4)`
C. `LiAlH_(4)`
D. `Pt//H_(2)`

Explanation

To solve the question regarding the conversion of 2-Hexyne to cis-2-Hexene, we need to analyze the reactions that can lead to this transformation.

### Step-by-Step Solution:

1. **Identify the Starting Material**:
- The starting material is 2-Hexyne, which has the structure:
\[ \text{CH}_3\text{C} \equiv \text{C}\text{CH}_2\text{CH}_3 \]
- This compound is an alkyne with a triple bond between the second and third carbon atoms.

2. **Understanding the Reaction Conditions**:
- To convert an alkyne to a cis-alkene, we typically need to use a specific type of catalyst. One common method is using a Lindlar catalyst, which is a poisoned palladium catalyst.

3. **Reaction with Lindlar Catalyst**:
- When 2-Hexyne is treated with a Lindlar catalyst (Pd/BaSO4), it undergoes partial hydrogenation. This process selectively reduces the triple bond to a double bond while maintaining the cis configuration.
- The reaction can be represented as:
\[ \text{CH}_3\text{C} \equiv \text{C}\text{CH}_2\text{CH}_3 \xrightarrow{\text{H}_2, \text{Lindlar}} \text{cis-2-Hexene} \]

4. **Product Formation**:
- The product of this reaction is cis-2-Hexene, which has the structure:
\[ \text{CH}_3\text{CH}=\text{CH}\text{CH}_2\text{CH}_3 \]
- In this structure, the two substituents (the two CH3 groups) are on the same side of the double bond, confirming the cis configuration.

5. **Conclusion**:
- Therefore, the treatment of 2-Hexyne with a Lindlar catalyst results in the formation of cis-2-Hexene.

### Final Answer:
2-Hexyne gives cis-2-Hexene on treatment with Lindlar catalyst (Pd/BaSO4).

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