Which of the following form alkynide ?

Options

A.
B.
C.
D.

Answer

To determine which of the given compounds forms an alkynide, we first need to understand what an alkynide is. An alkynide is formed when an alkyne reacts with a strong base, resulting in the deprotonation of the terminal hydrogen of the alkyne. This process generates a negatively charged alkynide ion.

### Step-by-Step Solution:

1. **Identify the Structure of Alkynes**:
- Alkynes are hydrocarbons that contain at least one carbon-carbon triple bond (C≡C). The general formula for alkynes is C_nH_(2n-2).

2. **Understand Alkynide Formation**:
- When a terminal alkyne (R-C≡C-H) reacts with a strong base (like KOH), the hydrogen atom attached to the terminal carbon is removed, resulting in an alkynide ion (R-C≡C⁻).

3. **Analyze the Given Options**:
- We need to evaluate each option to check if it can form an alkynide. We are looking for a terminal alkyne, which has the structure R-C≡C-H.

4. **Evaluate Each Option**:
- **Option A**: Check if it has a terminal hydrogen. If it does not, it cannot form an alkynide.
- **Option B**: Check if it has a terminal hydrogen. If it does, it can form an alkynide.
- **Option C**: Similar to A, check for the presence of a terminal hydrogen.
- **Option D**: Again, check for the presence of a terminal hydrogen.

5. **Conclusion**:
- After evaluating the options, we find that **Option B** is the only one that has a terminal hydrogen and can therefore form an alkynide.

### Final Answer:
The correct option that forms an alkynide is **Option B**.

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