Which of the following can yield acetylene in one step?

Options

A. Propyne
B. Ethene
C. Ethylene dichloride
D. Sodlum acetate

Explanation

To determine which of the given compounds can yield acetylene (C2H2) in one step, we will analyze each option provided:

1. **Propylene (C3H6)**:
- Propylene is an alkene and does not directly yield acetylene in a single step. It can undergo various reactions, but it cannot be converted to acetylene without multiple steps.

2. **Ethene (C2H4)**:
- Ethene is also an alkene. While it can be involved in reactions that may lead to acetylene, it does not convert to acetylene in one step.

3. **Ethylene Dichloride (C2H4Cl2)**:
- Ethylene dichloride can yield acetylene in one step through a dehydrohalogenation reaction. When ethylene dichloride reacts with a strong base like potassium hydroxide (KOH), it eliminates HCl and forms acetylene:
\[ \text{C}_2\text{H}_4\text{Cl}_2 + 2 \text{KOH} \rightarrow \text{C}_2\text{H}_2 + 2 \text{KCl} + 2 \text{H}_2\text{O} \]
- This shows that ethylene dichloride can indeed yield acetylene directly in one step.

4. **Sodium Acetate (CH3COONa)**:
- Sodium acetate does not yield acetylene in a single step. It can be involved in reactions that may produce acetylene, but it requires multiple steps.

Based on the analysis above, the compound that can yield acetylene in one step is **ethylene dichloride**.

### Final Answer:
The correct answer is **option 3: Ethylene dichloride**.