Chapter 11, Problem 11.134CHP

(a)

Interpretation Introduction

Interpretation:

The molality of the given solution has to be calculated.

Concept Introduction:

Molality of a solution also called as molal concentration can be defined as the mass of solute in grams to the mass of the solvent in kilograms. It can be given by the equation,

$\text{Molality}\text{(mol}{\text{kg}}^{\text{-1}}\text{)}\text{=}\frac{\text{Mass}\text{of}\text{solute}\text{(in}\text{g)}}{\text{Mass}\text{of}\text{solvent}\text{(in}\text{kg)}}$

(b)

Interpretation Introduction

Interpretation:

The freezing point of the solution, assuming complete dissociation of $\text{KI}$ 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,

$\begin{array}{l}\text{ΔT}\text{=}{\text{iK}}_{\text{f}}{\text{m}}_{\text{solute}}\mathrm{......}(2)\\ \text{ΔT is boiling-point elevation}\\ {\text{K}}_{\text{f}}\text{is}\text{molal freezing-point depression constant}\\ \text{m}\text{is }\text{molality of the solute}\\ \text{i}\text{is}\text{the}\text{van't Hoff factor}\end{array}$

(c)

Interpretation Introduction

Interpretation:

The percent of the $\text{KI}$ dissociated 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,

$\begin{array}{l}\text{ΔT}\text{=}{\text{iK}}_{\text{f}}{\text{m}}_{\text{solute}}\mathrm{......}(2)\\ \text{ΔT is boiling-point elevation}\\ {\text{K}}_{\text{f}}\text{is}\text{molal freezing-point depression constant}\\ \text{m}\text{is }\text{molality of the solute}\\ \text{i}\text{is}\text{the}\text{van't Hoff factor}\end{array}$