Chapter 11, Problem 11.116CHP

Interpretation Introduction

Interpretation:

The boiling point and freezing point of seawater with $3.5\text{ mass \%}$ solution of $\text{NaCl}$ has to be calculated.

Concept introduction:

• Depression in freezing point:

  The freezing point the solution is decreases when the solute is dissolved in the solvent is called depression in freezing point.  It is one of the colligative Properties thus,

$\begin{array}{l}\text{ΔT}\text{=}{\text{K}}_{\text{f}}{\text{m}}_{\text{solute}}\mathrm{......}(2)\\ \text{ΔT is boiling-point elevation}\\ {\text{K}}_{\text{f}}\text{is}\text{molal freezing-point depression constant}\\ \text{m}\text{is }\text{molality of the solute}\end{array}$

• Elevation of boiling point:

  The boiling point of the solution is increases when the solute is dissolved in the solvent is called Elevation of boiling point.  It is one of the colligative Properties thus,

$\begin{array}{l}\text{ΔT}\text{=}{\text{iK}}_{\text{b}}{\text{m}}_{\text{solute}}\mathrm{......}(1)\\ \text{ΔT is boiling-point elevation}\\ {\text{K}}_{\text{b}}\text{is}\text{molal boiling-point elevation constant}\\ \text{m}\text{is }\text{molality of the solute}\\ \text{i}\text{is}\text{the}\text{van't Hoff factor}\end{array}$