Question

The freezing point depression constant (\( K_f \)) for water is \( 1.86 \, {°C·kg/mol} \). If 0.5 moles of a non-volatile solute is dissolved in 1 kg of water, calculate the freezing point depression.

• A. \( 0.93 \, \text{°C} \)
• B. \( 1.86 \, \text{°C} \)
• C. \( 3.72 \, \text{°C} \)
• D. \( 2.79 \, \text{°C} \)

Hint:

The freezing point depression depends on the molality of the solution. For non-volatile solutes, the freezing point of the solvent decreases by \( \Delta T_f = K_f \times m \).