Chapter 8, Problem 8.116EP

(a)

Interpretation Introduction

Interpretation:

The lowest vapor pressure is for $\text{1}\text{.0}\text{M}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ or $\text{1}\text{.0}\text{M}\text{NaCl}$ has to be determined.

Concept Introduction:

Colligative properties: Properties of solutions which having influence on the concentration of the solute in it. Colligative properties are given below:

• Decrease in the vapor pressure
• Increase in the boiling point
• Decline in the freezing point
• Osmotic pressure

Vapor pressure of a liquid: Vapor pressure is defined as the pressure exerted by vapors of liquids when the equilibrium is established between liquid and its vapor.

(b)

Interpretation Introduction

Interpretation:

The highest boiling point is for $\text{1}\text{.0}\text{M}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ or $\text{1}\text{.0}\text{M}\text{NaCl}$ has to be determined.

Concept Introduction:

Boiling point is the temperature at which liquid turns into a gas. Example: boiling point of water is $\text{100°C}$. That is water changes from liquid phase to gas phase.

${\text{ΔT}}_{\text{b}}{\text{= T}}_{\text{b}}-{\text{T}}_{\text{b}}^{\text{°}}$

Where,

${\text{ΔT}}_{\text{b}}-$ Change in boiling point

${\text{T}}_{\text{b}}\text{ - }$ Boiling point of the solution

${\text{T}}_{\text{b}}^{\text{°}}\text{ - }$ Boiling point of pure solvent

Boiling point elevation$(\Delta T_b)$ is distinction between boiling point of the pure solvent ${\text{(T}}_{\text{b}}^{\text{°}}\text{)}$ and the boiling point of the solution ${\text{(T}}_{\text{b}}\text{)}$.

${\text{ΔT}}_{\text{b}}{\text{= iK}}_{\text{b}}\text{m}$

Where,

${\text{ΔT}}_{\text{b}}$ is the change in boiling point

${\text{K}}_{\text{b}}$ is the Molar boiling point constant

M is the molality of the solution

i is Van’t Hoff factor

Note:

The boiling point of one kilogram of water will be increase by $\text{0}\text{.51°C}$ by the addition of one mole of solute particles.

(c)

Interpretation Introduction

Interpretation:

The lowest freezing point is for $\text{1}\text{.0}\text{M}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ or $\text{1}\text{.0}\text{M}\text{NaCl}$ has to be determined.

Concept Introduction:

Freezing point is the temperature at which liquid turns into solid.

Freezing point depression${\text{(ΔT}}_{\text{f}}\text{)}$ is distinction between freezing point of the pure solvent ${\text{(T}}_{\text{f}}^{\text{°}}\text{)}$ and the freezing point of the solution ${\text{(T}}_{\text{f}}\text{)}$.

${\text{ΔT}}_{\text{f}}{\text{= K}}_{\text{f}}\text{m}$

Where,

${\text{ΔT}}_{\text{f}}-$ Change in freezing point

${\text{K}}_{\text{f}}-$ Molar freezing point constant

m- Molality of the solution

Note:

The freezing point of one kilogram of water will be lower by $\text{1}\text{.86°C}$ by the addition of one mole of solute particles.

(d)

Interpretation Introduction

Interpretation:

The lower osmotic pressure is for $\text{1}\text{.0}\text{M}{\text{Na}}_{\text{2}}{\text{SO}}_{\text{4}}$ or $\text{1}\text{.0}\text{M}\text{NaCl}$ has to be determined.

Concept Introduction:

Osmotic pressure is the pressure that is needed to stop osmosis. Osmotic pressure of the solution is directly proportional to the concentration of the solution.

In osmosis, the passage of solvent from a dilute solution to a more concentrated solution occurs through a semipermeable membrane.