Which of the following hydrocarbon can decolourise bromine water?

Options

A. `C_(4)H_(6)`
B. `C_(4)H_(8)`
C. `C_(3)H_(6)`
D. all these

Explanation

To determine which hydrocarbons can decolourise bromine water, we need to identify the unsaturated hydrocarbons among the given options. Unsaturated hydrocarbons contain either double bonds (alkenes) or triple bonds (alkynes).

### Step-by-Step Solution:

1. **Understand the Concept of Unsaturation**:
- Unsaturated hydrocarbons are those that contain at least one double bond (alkenes) or triple bond (alkynes). These bonds can react with bromine, leading to the decolourisation of bromine water.

2. **Examine the Given Hydrocarbons**:
- Let's analyze the hydrocarbons provided:
- **C4H6**: This hydrocarbon can be represented as having a triple bond (alkyne), which makes it unsaturated.
- **C4H8**: This hydrocarbon can have a double bond (alkene), indicating it is also unsaturated.
- **C3H6**: This hydrocarbon can also have a double bond (alkene), confirming it as unsaturated.

3. **Conclusion**:
- Since all three hydrocarbons (C4H6, C4H8, and C3H6) are unsaturated, they can all decolourise bromine water.

4. **Final Answer**:
- Therefore, all of the given hydrocarbons can decolourise bromine water.