The reagent used for obtaining trans alkene from alkyl subsituted acetylene with hydrogen is

Options

A. Na in liq. `NH_(3)`
B. `LiAlH_(4)`
C. `Zn+HCl`
D. `H_(2)` in presence of Ni

Explanation

To obtain a trans alkene from alkyl substituted acetylene using hydrogen, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Starting Material**:
We start with an alkyl substituted acetylene, which is a type of alkyne. Alkynes have a triple bond between carbon atoms.

2. **Select the Appropriate Reaction**:
To convert an alkyne to an alkene, we need to perform a reduction reaction. The goal is to obtain a trans alkene, which has substituents on opposite sides of the double bond.

3. **Choose the Reducing Agent**:
For the specific transformation of alkyl substituted acetylene to trans alkene, we can use Birch Reduction. This involves the use of sodium metal in liquid ammonia.

4. **Perform the Reaction**:
In the Birch Reduction, sodium (Na) is dissolved in liquid ammonia (NH3). This creates a strong reducing environment that facilitates the conversion of the alkyne to a trans alkene.

5. **Result**:
The product of this reaction will be the desired trans alkene.

### Final Answer:
The reagent used for obtaining trans alkene from alkyl substituted acetylene with hydrogen is **sodium in liquid ammonia**.

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