An example of colligative property is

Options

A. Freezing point
B. Boiling point
C. Vapour pressure
D. Osmotic pressure

Explanation

To solve the question about identifying an example of a colligative property, we will follow these steps:

### Step-by-Step Solution:

1. **Understand Colligative Properties**:
- Colligative properties are properties of solutions that depend on the number of solute particles in a given amount of solvent, rather than the identity of the solute particles.

2. **Identify the Common Colligative Properties**:
- The main colligative properties include:
- **Osmotic Pressure (π)**: The pressure required to stop the flow of solvent into the solution through a semipermeable membrane.
- **Depression in Freezing Point (ΔTf)**: The decrease in the freezing point of a solvent when a solute is added.
- **Elevation in Boiling Point (ΔTb)**: The increase in the boiling point of a solvent when a solute is added.
- **Relative Lowering of Vapor Pressure (ΔP/P0)**: The decrease in vapor pressure of a solvent when a solute is added.

3. **Evaluate the Options**:
- If the question provides options, we need to evaluate each one to determine if it is a colligative property.
- For example:
- Freezing point (not a colligative property)
- Boiling point (not a colligative property)
- Vapor pressure (not a colligative property)
- Osmotic pressure (is a colligative property)

4. **Select the Correct Answer**:
- Based on the evaluation, the correct answer would be the one that mentions osmotic pressure, as it is a recognized colligative property.

### Conclusion:
The correct answer to the question "An example of colligative property is" is **Osmotic Pressure**.