2-Butyne can be prepared from which of following compounds?

Options

A. `CH_3-underset(Cl)underset(|)overset(Cl)overset(|)C-underset(Cl)underset(|)overset(Cl)overset(|)C-CH_3`
B. `CH_3-CH_2-underset(Br)underset(|)overset(Br)overset(|)C-CH_3`
C. `underset(Cl)underset(|)(CH_2)-CH_2-CH_2-underset(Cl)underset(|)(CH_2)`
D. Both A and B

Answer

To determine which compound can be converted into 2-butyne, we need to analyze the given compounds and the reactions that can be performed on them.

### Step-by-Step Solution:

1. **Identify the structure of 2-butyne**:
2-butyne is an alkyne with the formula C4H6, specifically with a triple bond between the second and third carbon atoms (CH3-C≡C-CH3).

2. **Analyze the first compound (CH3CCl)**:
- When CH3CCl is treated with silver (Ag) in the presence of heat, it undergoes a reaction to form 2-butyne:
\[ \text{CH}_3\text{CCl} + \text{Ag} \xrightarrow{\text{heat}} \text{CH}_3\text{C} \equiv \text{C}\text{CH}_3 + 4 \text{AgCl} \]
- This reaction results in the formation of 2-butyne.

3. **Analyze the second compound (CH3CH2CBr2)**:
- When CH3CH2CBr2 is treated with sodium amide (NaNH2), it undergoes dehydrohalogenation:
\[ \text{CH}_3\text{CH}_2\text{CBr}_2 + 2 \text{NaNH}_2 \rightarrow \text{CH}_3\text{C} \equiv \text{C}\text{CH}_3 + 2 \text{NaBr} + 2 \text{NH}_3 \]
- This reaction also leads to the formation of 2-butyne.

4. **Analyze the third compound (CH2=CH-CH2-Cl)**:
- When this compound reacts with NaNH2, it can lead to the formation of 1,4-butadiene instead of 2-butyne:
\[ \text{CH}_2\text{=CH-CH}_2\text{Cl} + \text{NaNH}_2 \rightarrow \text{CH}_2\text{=CH-C} \equiv \text{C} + \text{NaCl} + \text{NH}_3 \]
- This does not produce 2-butyne.

5. **Conclusion**:
- The first two compounds (CH3CCl and CH3CH2CBr2) can be converted into 2-butyne, while the third compound does not yield 2-butyne.

### Final Answer:
2-butyne can be prepared from the following compounds:
- CH3CCl
- CH3CH2CBr2