The vapour pressure of a dilute solution of a solute is influeneced by:

Options

A. temperature of solution
B. melting point of solute
C. mole fraction of solute
D. degree of dissociation of solute

Answer

To determine the factors that influence the vapor pressure of a dilute solution of a solute, we can analyze each option provided in the question. Here’s a step-by-step solution:

### Step 1: Understand the Concept of Vapor Pressure
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid or solid phase. In a solution, the presence of a solute affects the vapor pressure of the solvent.

**Hint:** Remember that vapor pressure is related to the tendency of molecules to escape from the liquid phase into the vapor phase.

### Step 2: Analyze the Options
1. **Temperature of the solution (Option A)**:
- The vapor pressure of a solution increases with an increase in temperature. This is because higher temperatures provide more energy to the molecules, allowing more of them to escape into the vapor phase.
- **Conclusion**: This option is correct.

**Hint:** Think about how heating a liquid affects the movement of its molecules.

2. **Melting point of the solute (Option B)**:
- The melting point of the solute does not directly influence the vapor pressure of the solution. It is more related to the physical state of the solute rather than its effect on the vapor pressure of the solvent.
- **Conclusion**: This option is not correct.

**Hint:** Consider how the state of the solute (solid, liquid) affects the solution's properties.

3. **Mole fraction of solute (Option C)**:
- The vapor pressure of a solvent in a solution is lowered by the addition of a non-volatile solute. The relative lowering of vapor pressure can be expressed using the mole fraction of the solute.
- **Conclusion**: This option is correct.

**Hint:** Recall the formula for relative lowering of vapor pressure: \( \frac{P_0 - P}{P_0} = X_B \).

4. **Degree of dissociation of solute (Option D)**:
- If the solute is an electrolyte, its degree of dissociation (α) affects the number of particles in solution. More particles lead to a greater lowering of vapor pressure.
- **Conclusion**: This option is correct.

**Hint:** Think about how dissociation increases the number of solute particles in the solution.

### Step 3: Summarize the Influencing Factors
Based on the analysis:
- The vapor pressure of a dilute solution is influenced by:
- Temperature of the solution (Option A)
- Mole fraction of solute (Option C)
- Degree of dissociation of solute (Option D)

**Final Answer**: The correct options are A, C, and D.