Which of the following statements are correct ?
(i) Colligative property depends upon number of particles of solute present in the solution.
(ii) Relative lowering of vapour pressure of a solution is equal to the mole fraction of the non-volatile non-electrolyte solute.

Options

A. i
B. ii
C. Both i and ii
D. None of these

Answer

To determine the correctness of the statements provided in the question, we will analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement (i): Colligative property depends upon the number of particles of solute present in the solution.**

- **Explanation**: Colligative properties are properties of solutions that depend on the number of solute particles in a given amount of solvent, rather than the identity of the solute. Examples of colligative properties include vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure. Therefore, this statement is correct.

### Step 2: Analyze the second statement
**Statement (ii): Relative lowering of vapor pressure of a solution is equal to the mole fraction of the non-volatile non-electrolyte solute.**

- **Explanation**: The relative lowering of vapor pressure can be described by Raoult's law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent. The relative lowering of vapor pressure is given by the formula:

\[ \text{Relative lowering of vapor pressure} = \frac{P^0 - P}{P^0} = \frac{n_{solute}}{n_{solute} + n_{solvent}} \]

For a dilute solution, this can be approximated to the mole fraction of the solute. Thus, for a non-volatile non-electrolyte solute, the relative lowering of vapor pressure is indeed equal to the mole fraction of the solute. Therefore, this statement is also correct.

### Conclusion
Both statements (i) and (ii) are correct.

### Final Answer
Both statements are correct.

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