Which statement comparing solutions with pure solvent is not correct

Options

A. A solution containing a non-volatile solute has a lower vapour pressure than pure solvent
B. A solution containing a non-volatile solute has a lower boiling point than pure solvent
C. A solution containing a non-volatile solute has a lower freezing point than pure solvent
D. A solution will have a greater mass than an equal volume of pure solvent if the solute has a molar mass greater than the solvent

Explanation

To solve the question regarding which statement comparing solutions with pure solvents is not correct, let's analyze each option step by step.

### Step 1: Understand the Properties of Solutions
When a non-volatile solute is added to a pure solvent, it affects the physical properties of the solvent, such as vapor pressure, boiling point, and freezing point.

### Step 2: Analyze Each Statement
1. **Statement A**: "A solution containing a non-volatile solute has a lower vapor pressure than pure solvent."
- This statement is **correct**. The addition of a non-volatile solute decreases the vapor pressure of the solvent due to the solute particles occupying space at the surface and reducing the number of solvent molecules that can escape into the vapor phase.

2. **Statement B**: "A solution containing a non-volatile solute has a lower boiling point than pure solvent."
- This statement is **not correct**. In fact, a solution with a non-volatile solute typically has a higher boiling point than the pure solvent. This phenomenon is known as boiling point elevation.

3. **Statement C**: "A solution containing a non-volatile solute has a lower freezing point than pure solvent."
- This statement is **correct**. The presence of a solute lowers the freezing point of the solvent, a phenomenon known as freezing point depression.

4. **Statement D**: "A solution will have a greater mass than an equal volume of pure solvent if the solute has a molar mass greater than the solvent."
- This statement is **correct**. The mass of the solution will increase due to the added solute, especially if the solute has a greater molar mass than the solvent.

### Step 3: Identify the Incorrect Statement
From the analysis above, we can conclude that **Statement B** is the one that is not correct. A solution containing a non-volatile solute has a higher boiling point than the pure solvent, not a lower one.

### Final Answer
The statement that is not correct is: **"A solution containing a non-volatile solute has a lower boiling point than pure solvent."**

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