Question

What is the freezing point of a 0.82 m aqueous solution of a non-volatile non-electrolyte?

Answer 1

Answer:

-1.5 °C

Explanation:

The freezing-point depression is a colligative property, that is, the property of a solution. The freezing point of a solution is lower than the freezing point of the pure solvent. We can find the freezing-point depression of a solution of a non-volatile non-electrolyte solute using the following expression.

$\Delta T_f = K_f \times b$

where,

• $\Delta T_f$: the freezing-point depression

• $K_f$:  cryoscopic constant (For water, Kf = 1.86 °C/m)

• $b$: molality

$\Delta T_f = \frac{1.86\°C}{m} \times 0.82m = 1.5\°C$

The freezing-point of pure water is 0°C. The freezing-point of the solution is:

$0\°C-1.5\°C = -1.5\°C$