Chapter 13, Problem 13.70QP

Interpretation Introduction

Interpretation:

The decreasing order of freezing point from the given aqueous solution is to be determined.

Concept Introduction:

Freezing point depression: The freezing point of the solution varies with the solute concentration.

$\begin{array}{c}\text{Freezing point depression = }\Delta {\text{T}}_{fp}{\text{= K}}_{fp}{\text{. m}}_{solute}\text{.i,}\\ \text{where,}{\text{K}}_{fp}\text{=}\text{molal freezing point depression constant,}\\ {\text{m}}_{solute}\text{= molality of solute,}\\ \text{i}\text{=}\text{van't}\text{Hoff}\text{factor}\text{.}\end{array}$

Decline in the freezing point is huge when solute is an electrolyte than when solute is nonelectrolyte.

van’t Hoff factor (i): it is the ratio between change in in freezing point measured and change in in freezing point calculated. It indicates the total number of ions that are produced.

Molality (m): Molality is the number of moles of solute present in one kilogram of solvent.

$\text{Molality (m) =}\frac{\text{Number}\text{of}\text{moles}\text{of}\text{solute}}{\text{1kg}\text{of}\text{solvent}}$

Freezing point of a solution decreases with the increase in concentration of the solute in solution.