In the reaction given below `H-C -= C - H + H - C -= C - H underset(NH_4Cl)overset(Cu_2Cl)(rarr)(x)`, 'X' will be

Options

A. `CH_2 = CH - C -= CH`
B. `CU - C -= C - Cu`
C. `CH -= C - Cu`
D. `CH -= C - C -= CH`

Answer

To solve the problem, we need to analyze the reaction of the alkyne with copper(II) chloride (Cu₂Cl₂) in the presence of ammonium chloride (NH₄Cl). The alkyne given is 1-butyne (H-C≡C-H) and it is reacting with itself.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants are two molecules of 1-butyne (H-C≡C-H) and the reagents are Cu₂Cl₂ and NH₄Cl.

2. **Mechanism of Reaction**:
- The presence of NH₄Cl provides Cl⁻ ions.
- The Cl⁻ ion can attack the hydrogen atom of the alkyne, leading to the formation of a carbanion (C⁻) at the carbon where the hydrogen was removed.

3. **Formation of Carbanion**:
- When Cl⁻ attacks one of the hydrogen atoms of the alkyne, it creates a carbanion:
\[ H-C≡C-H + Cl^- \rightarrow H-C≡C^-- + HCl \]

4. **Nucleophilic Attack**:
- The carbanion formed can then attack the other alkyne molecule. The negative charge on the carbanion will attack the carbon of the second alkyne molecule:
\[ H-C≡C^- + H-C≡C-H \rightarrow H-C≡C-C-H \]

5. **Formation of the Final Product**:
- The reaction results in the formation of a new compound where a new bond is formed between the two alkyne molecules, resulting in a product that has a triple bond and a single bond:
\[ H-C≡C-C-H \]
- This product is 1,3-butadiene (H-C≡C-C-H).

6. **Conclusion**:
- The final product 'X' is 1,3-butadiene.

### Answer:
The product 'X' will be 1,3-butadiene.

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