Chapter 12, Problem 12.103QE

(a)

Interpretation Introduction

Interpretation:

The molality of the solute in each of the two solutions has to be calculated.

Concept Introduction:

Freezing point depression:  The freezing point depression is proportional to the concentration of the solute particles and is given by the equation,

  ${\text{ΔT}}_{\text{f}}{\text{=imk}}_{\text{f}}$

Here,

  ${\text{ΔT}}_{\text{f}}\text{=}$ Freezing point of the solution

  $\text{m=}$ Molal concentration

  ${\text{k}}_{\text{f}}\text{=}$ Freezing point depression constant (depends on the solvent used).

  $\text{i=}$ van’t Hoff factor

(b)

Interpretation Introduction

Interpretation:

The van’t Hoff factors for benzene and water solutions have to be given.

Concept Introduction:

van’t Hoff factor, i:  The van’t Hoff factor is given by the equation,

  $\text{i=}\frac{\text{measured}\text{colligative}\text{property}}{\text{expected}\text{value}\text{for}\text{a}\text{nonelectrolyte}}$

For solutions that are nonelectrolytes, like urea and sucrose, the van’t Hoff factor is one.  For solutions of salts and other electrolytes, the value of i is greater than one.  For dilute solution such as ($\text{0}\text{.01m}$ or less), the van’t Hoff factor will be equal to the number of ions formed by each formula unit of the compound that dissolves.

(c)

Interpretation Introduction

Interpretation:

The difference in the van’t Hoff factors of acetic acid in benzene solution and water solution has to be explained