If pressure is applied to the equilibrium ofsolid ` hArr` liquid. The melting point of the solid

Options

A. will not change
B. may increase or decrease depending upon the nature of solid
C. will always increase
D. will always decrease

Answer

To solve the question regarding the effect of pressure on the melting point of a solid in equilibrium with its liquid, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Solid-Liquid Equilibrium**:
- In a solid-liquid equilibrium, both the solid and liquid phases coexist. The melting point is the temperature at which the solid turns into liquid.

2. **Effect of Pressure on Phase Equilibrium**:
- According to Le Chatelier's principle, if an external pressure is applied to a system at equilibrium, the system will adjust to counteract that change.

3. **Types of Solids**:
- There are two types of solid-liquid equilibria based on the volume changes during melting:
- **Type A**: The solid has a greater volume than the liquid (e.g., ice to water).
- **Type B**: The solid has a lesser volume than the liquid (e.g., paraffin).

4. **Analyzing Type A (e.g., Ice)**:
- In the case of ice (solid) melting into water (liquid), the volume of solid (ice) is greater than that of the liquid (water).
- When pressure is applied, the melting point decreases because the system shifts towards the phase with a smaller volume (liquid).

5. **Analyzing Type B (e.g., Paraffin)**:
- For most solids like paraffin, the volume of the solid is less than that of the liquid.
- In this case, applying pressure increases the melting point because the system shifts towards the phase with a larger volume (liquid).

6. **Conclusion**:
- The effect of pressure on the melting point of a solid depends on the nature of the solid:
- For solids that expand upon melting (Type A), increasing pressure lowers the melting point.
- For solids that contract upon melting (Type B), increasing pressure raises the melting point.
- Therefore, the melting point of the solid will either increase or decrease depending on its nature.

### Final Answer:
The melting point of the solid will change depending on the nature of the solid: it may increase or decrease with applied pressure.