The catalyst used to reduce an alkyne to alkene is

Options

A. Raney Nickel
B. Pallaidium
C. Lindlar's catalyst
D. Iron

Answer

To solve the question regarding the catalyst used to reduce an alkyne to an alkene, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- We start with an alkyne, which is a hydrocarbon containing a carbon-carbon triple bond (C≡C). The goal is to reduce this alkyne to an alkene, which has a carbon-carbon double bond (C=C).

2. **Catalysts for Reduction**:
- Common catalysts for the hydrogenation of alkynes include metals such as platinum (Pt), palladium (Pd), and nickel (Ni). However, these catalysts can fully hydrogenate alkynes to alkanes (C-C single bond).

3. **Stopping the Reaction**:
- To specifically stop the reaction at the alkene stage and not go further to alkanes, we need a modified catalyst. This is where the concept of a poisoned catalyst comes into play.

4. **Lindlar's Catalyst**:
- Lindlar's catalyst is a specific type of palladium catalyst that has been poisoned (deactivated) with lead and quinoline. This catalyst allows for the partial hydrogenation of alkynes to alkenes without further reduction to alkanes.

5. **Conclusion**:
- Therefore, the catalyst used to reduce an alkyne to an alkene is **Lindlar's catalyst**.

### Final Answer:
The catalyst used to reduce an alkyne to an alkene is **Lindlar's catalyst**.

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