Of the following, unsaturated hydrocarbons are -

Options

A. Ethyne
B. Cyclohexane
C. n-propane
D. Ethane

Answer

To determine which of the given compounds are unsaturated hydrocarbons, we need to identify whether they contain carbon-carbon double or triple bonds. Unsaturated hydrocarbons are characterized by the presence of these types of bonds, while saturated hydrocarbons only have single bonds.

### Step-by-Step Solution:

1. **Identify the Compounds**: We have four options to analyze:
- Option 1: Ethyne
- Option 2: Cyclohexane
- Option 3: N-propane
- Option 4: Ethane

2. **Analyze Option 1: Ethyne (C2H2)**:
- Ethyne has a structure with two carbon atoms connected by a triple bond (C≡C).
- Since it contains a triple bond, Ethyne is classified as an unsaturated hydrocarbon.

3. **Analyze Option 2: Cyclohexane (C6H12)**:
- Cyclohexane is a cyclic compound with six carbon atoms connected by single bonds.
- There are no double or triple bonds present in Cyclohexane.
- Therefore, Cyclohexane is a saturated hydrocarbon.

4. **Analyze Option 3: N-propane (C3H8)**:
- N-propane has a linear structure with three carbon atoms connected by single bonds.
- There are no double or triple bonds in N-propane.
- Thus, N-propane is also a saturated hydrocarbon.

5. **Analyze Option 4: Ethane (C2H6)**:
- Ethane consists of two carbon atoms connected by a single bond.
- Similar to the previous compounds, there are no double or triple bonds present.
- Hence, Ethane is a saturated hydrocarbon.

6. **Conclusion**:
- After analyzing all four options, we find that only Ethyne is an unsaturated hydrocarbon.
- Therefore, the correct answer is **Option 1: Ethyne**.

### Summary:
- **Unsaturated Hydrocarbon**: Ethyne (Option 1)
- **Saturated Hydrocarbons**: Cyclohexane (Option 2), N-propane (Option 3), Ethane (Option 4)