How does the surface tension of a liquid vary with increase in temperature ?

Options

A. Remains same
B. Decreases
C. Increases
D. No regular pattern is followed .

Explanation

### Step-by-Step Solution:

1. **Understanding Surface Tension**:
- Surface tension is a property of the liquid surface that causes it to contract to the smallest possible surface area. This is why droplets of liquid tend to form a spherical shape, as a sphere has the minimum surface area for a given volume.

2. **Cohesive Forces**:
- Surface tension arises due to cohesive forces, which are the intermolecular forces of attraction between the molecules in the liquid. These forces create an imbalance at the surface of the liquid, leading to the phenomenon of surface tension.

3. **Effect of Temperature on Kinetic Energy**:
- When the temperature of a liquid increases, the kinetic energy of its molecules also increases. This increase in kinetic energy causes the molecules to move more vigorously.

4. **Impact on Intermolecular Forces**:
- As the kinetic energy increases, the intermolecular forces of attraction between the molecules decrease. This is because the increased movement of the molecules makes it harder for them to stay close together.

5. **Conclusion on Surface Tension**:
- Since surface tension is directly related to the strength of the intermolecular forces, a decrease in these forces leads to a decrease in surface tension. Therefore, as the temperature increases, the surface tension of the liquid decreases.

6. **Final Answer**:
- The surface tension of a liquid decreases with an increase in temperature.