Chapter 17, Problem 88E

(a)

Interpretation Introduction

Interpretation:

The freezing point and boiling point of 0.050 m MgCl₂ solution needs to be deduced

Concept Introduction:

The depression in freezing point ( ${\text{ΔT}}_{\text{f}}$ ) of a solution in the presence of a solute of molality ( m ) is given as:

  $\begin{array}{l}{\text{ΔT}}_{\text{f}}{\text{ = T}}_{\text{f}}^{\text{0}}-{\text{ T}}_{\text{f}}\\ {\text{ΔT}}_{\text{f}}{\text{=i(K}}_{\text{f}}\text{×m) -----(1)}\end{array}$

Here,

  ${\text{T}}_{\text{f}}^{\text{0}}$ and ${\text{T}}_{\text{f}}$ are the freezing points of the pure solvent and solution respectively

K_f denotes the freezing point depression constant

i represents the Von’t Hoff factor

The elevation in boiling point ( ${\text{ΔT}}_{\text{b}}$ ) of a solution in the presence of a solute of molality ( m ) is given as:

  $\begin{array}{l}{\text{ΔT}}_{\text{b}}{\text{ = T}}_{\text{b}}-{\text{T}}_{\text{b}}^{\text{0}}\\ {\text{ΔT}}_{\text{b}}{\text{=i(K}}_{\text{b}}\text{×m) ----(2)}\end{array}$

Here,

  ${\text{ΔT}}_{\text{b}}$ and T_b are the boiling points of the pure solvent and solution respectively.

K_b denotes the boiling point elevation constant.

(b)

Interpretation Introduction

Interpretation:

The freezing point and boiling point of 0.050 m FeCl₃ solution needs to be deduced.

Concept Introduction:

The depression in freezing point ( ${\text{ΔT}}_{\text{f}}$ ) of a solution in the presence of a solute of molality ( m ) is given as:

  $\begin{array}{l}{\text{ΔT}}_{\text{f}}{\text{ = T}}_{\text{f}}^{\text{0}}-{\text{ T}}_{\text{f}}\\ {\text{ΔT}}_{\text{f}}{\text{=i(K}}_{\text{f}}\text{×m) -----(1)}\end{array}$

Here, ${\text{T}}_{\text{f}}^{\text{0}}$ and ${\text{T}}_{\text{f}}$ are the freezing points of the pure solvent and solution respectively.

K_f denotes the freezing point depression constant

i represents the Von’t Hoff factor

The elevation in boiling point ( ${\text{ΔT}}_{\text{b}}$ ) of a solution in the presence of a solute of molality ( m ) is given as:

  $\begin{array}{l}{\text{ΔT}}_{\text{b}}{\text{ = T}}_{\text{b}}-{\text{T}}_{\text{b}}^{\text{0}}\\ {\text{ΔT}}_{\text{b}}{\text{=i(K}}_{\text{b}}\text{×m) ----(2)}\end{array}$

Here,

  ${\text{ΔT}}_{\text{b}}$ andT_b are the boiling points of the pure solvent and solution respectively.

K_b denotes the boiling point elevation constant.