The vapour pressure of a dilute solution of a solute is not influenced by

Options

A. nature of the solute if it is non-electrolyte
B. mole fraction of the solute
C. melting point of the solute
D. degree of dissociation of the solute.

Answer

To solve the question regarding the vapor pressure of a dilute solution of a solute, we need to understand the factors that influence vapor pressure in solutions.

### Step-by-Step Solution:

1. **Understanding 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.

2. **Raoult's Law**:
According to Raoult's Law, the vapor pressure of a solvent in a solution is directly proportional to the mole fraction of the solvent in the solution. The equation is given by:
\[ P_{solution} = X_{solvent} \cdot P^0_{solvent} \]
where \( P_{solution} \) is the vapor pressure of the solution, \( X_{solvent} \) is the mole fraction of the solvent, and \( P^0_{solvent} \) is the vapor pressure of the pure solvent.

3. **Influence of Solute**:
The presence of a solute lowers the mole fraction of the solvent, which in turn lowers the vapor pressure of the solution compared to that of the pure solvent. This effect is more pronounced with non-volatile solutes.

4. **Nature of Solute**:
The vapor pressure of a dilute solution is not influenced by the nature of the solute if the solute is a non-electrolyte. Non-electrolytes do not dissociate into ions in solution, meaning they do not affect the vapor pressure as significantly as electrolytes do.

5. **Colligative Properties**:
The vapor pressure lowering is a colligative property, which depends on the number of solute particles in the solution rather than their identity. Therefore, the specific type of non-electrolyte solute does not influence the vapor pressure.

### Conclusion:
The vapor pressure of a dilute solution of a solute is not influenced by the nature of the solute when the solute is a non-electrolyte.