`C_(2)H_(2)` on addition with `H_(2)` forms ethane in presence of palladium catalayst but if reaction is carried in the presence of barium sulphate and quinoline , the product is ethene and not ethane . Why ?

Explanation

To understand why the addition of hydrogen to ethyne (C₂H₂) in the presence of barium sulfate and quinoline results in ethene (C₂H₄) instead of ethane (C₂H₆), we can break down the process step by step:

### Step-by-Step Solution:

1. **Identify the Reactants**:
The starting material is ethyne (C₂H₂), which is an alkyne. The other reactant is hydrogen gas (H₂).

2. **Catalyst Role**:
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