Question

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

PLEASE HELP

Answer 1

-1.5 °C

Step-by-step 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 * 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 = (1.86\°C)/(m) * 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`