Which of the following increases with the increase in temperature in case of a liquid?

Options

A. Vapour pressure
B. Surface tension
C. Viscosity
D. All of these

Answer

To determine which property of a liquid increases with an increase in temperature, we can analyze the effects of temperature on different properties of liquids: vapor pressure, surface tension, and viscosity.

### Step-by-Step Solution:

1. **Understanding Vapor Pressure:**
- As the temperature of a liquid increases, the kinetic energy of its molecules also increases. This means that more molecules have enough energy to escape the liquid phase and enter the vapor phase.
- Therefore, the vapor pressure of the liquid increases with an increase in temperature.

2. **Analyzing Surface Tension:**
- Surface tension is the property of a liquid that causes it to behave as if its surface is covered with a stretched elastic membrane.
- Generally, as temperature increases, the surface tension of a liquid decreases. This is because the increased kinetic energy allows the molecules to move more freely, reducing the cohesive forces at the surface.

3. **Examining Viscosity:**
- Viscosity is a measure of a liquid's resistance to flow. For most liquids, as the temperature increases, the viscosity decreases. This is because the increased kinetic energy allows the molecules to overcome intermolecular forces more easily, allowing them to flow more freely.

4. **Conclusion:**
- From the analysis above, we can conclude that the only property that increases with an increase in temperature for a liquid is **vapor pressure**.

### Final Answer:
The property that increases with an increase in temperature in the case of a liquid is **vapor pressure**.

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