Which of the following aqueous solution will show maximum vapour pressur at 300 K?

Options

A. 1 M NaCl
B. `1" M ""CaCl"_(2)`
C. `1" M ""AlCl"_(3)`
D. `1" M ""C"_(12)"H"_(22)"O"_(11)`

Explanation

To determine which aqueous solution will show the maximum vapor pressure at 300 K, we need to consider the concept of vapor pressure lowering in solutions. The vapor pressure of a solution is affected by the number of solute particles present, which is described by the van 't Hoff factor (i). The greater the number of particles in solution, the lower the vapor pressure.

### Step-by-Step Solution:

1. **Understand Vapor Pressure Lowering**:
The vapor pressure of a solution is lower than that of the pure solvent. The extent of this lowering depends on the concentration of the solute and its ability to dissociate into ions.

2. **Identify the van 't Hoff Factor (i)**:
The van 't Hoff factor (i) indicates the number of particles a solute produces in solution. For example:
- For a non-electrolyte like glucose (C6H12O6), which does not dissociate, i = 1.
- For electrolytes, the value of i depends on the number of ions produced upon dissociation.

3. **Evaluate Each Option**:
- **Glucose (non-electrolyte)**: i = 1 (does not dissociate)
- **NaCl (electrolyte)**: i = 2 (dissociates into Na⁺ and Cl⁻)
- **K2SO4 (electrolyte)**: i = 3 (dissociates into 2 K⁺ and SO₄²⁻)
- **CaCl2 (electrolyte)**: i = 3 (dissociates into Ca²⁺ and 2 Cl⁻)

4. **Determine Relative Lowering of Vapor Pressure**:
The relative lowering of vapor pressure is given by the formula:
\[ \text{Relative lowering} = \frac{\Delta P}{P^0} = \frac{n_{solute}}{n_{solvent}} \times i \]
Where \( n_{solute} \) is the number of moles of solute and \( n_{solvent} \) is the number of moles of solvent.

5. **Conclusion**:
The solution with the least relative lowering of vapor pressure will have the maximum vapor pressure. Since glucose has the lowest van 't Hoff factor (i = 1), it will show the maximum vapor pressure among the options provided.

### Final Answer:
The aqueous solution that will show the maximum vapor pressure at 300 K is the solution containing **glucose**.