Chapter 16, Problem 16.83P

Interpretation Introduction

Interpretation:

The molality of ethylene glycol in water solution that freezes at $-{40}^{\circ }C$ has to be calculated.

Concept Introduction:

Freezing point depression:

The lowering of the vapor pressure of a solvent by a solute leads to a lowering of the freezing point of the solution relative to that of the pure solvent.  This effect is called as the freezing point depression.  The mathematical relationship is given below.

  $\Delta T_f=T_f{}^{\circ }-T_f=K_f{m}_c$

Where, $\Delta T_f$ is freezing point depression, $T_f$ is the freezing point of solution, $T_f{}^{\circ }$ is the freezing point of pure solvent, $K_f$ is the freezing point depression constant and $m_c$ is the colligative molality.