Which of the following is an intensive property?

Options

A. Volume
B. Enthalpy
C. Surface tension
D. Free energy

Answer

To determine which of the given options is an intensive property, we need to understand the definitions of intensive and extensive properties.

### Step-by-Step Solution:

1. **Define Intensive and Extensive Properties**:
- **Intensive Property**: A property that does not depend on the amount of substance present. Examples include temperature, pressure, and density.
- **Extensive Property**: A property that depends on the amount of substance present. Examples include mass, volume, and enthalpy.

2. **Analyze Each Option**:
- **Option A: Volume**
- Volume is an extensive property because it changes with the amount of substance present.
- **Option B: Enthalpy**
- Enthalpy is also an extensive property as it depends on the quantity of the substance.
- **Option C: Surface Tension**
- Surface tension is an intensive property because it does not change with the amount of liquid present; it depends on the intermolecular forces at the surface.
- **Option D: Free Energy**
- Free energy is an extensive property as it varies with the amount of substance.

3. **Conclusion**:
- Among the options provided, **C. Surface Tension** is the only intensive property.

### Final Answer:
The answer to the question is **C. Surface Tension**.