Chapter 4, Problem 4.13P

(a)

Interpretation Introduction

Interpretation:

The partial vapour pressure of acetone for the mixture has to be determined.

Concept Introduction:

Raoult’s law:

The partial vapour pressure of a substance in a liquid mixture is proportional to its mole fraction in the mixture and its vapour pressure when pure.

Mathematically, it can be represented as

$p_J=X_J{p}_J^{\Theta }$

Where,

$p_J=$ Partial vapour pressure of a substance in the mixture

$X_J=$ Mole fraction

$p_J^{\Theta }=$ vapour pressure of a substance in its pure form

(b)

Interpretation Introduction

Interpretation:

The partial vapour pressure of chloroform for the mixture has to be determined.

Concept Introduction:

Raoult’s law:

The partial vapour pressure of a substance in a liquid mixture is proportional to its mole fraction in the mixture and its vapour pressure when pure. 

Mathematically, it can be represented as

$p_J=X_J{p}_J^{\Theta }$

Where,

$p_J=$ Partial vapour pressure of a substance in the mixture

$X_J=$ Mole fraction

$p_J^{\Theta }=$ vapour pressure of a substance in its pure form

Suppose two substances A and B mix together to form an ideal-dilute solution, then

Total pressure of the mixture (P) $=P_A+P_B$

Where,

$P_A=$ Partial pressure of a substance A in the mixture

$P_B=$ Partial pressure of a substance B in the mixture

(c)

Interpretation Introduction

Interpretation:

The Henry’s law constant of chloroform has to be determined.

Concept Introduction:

Henry’s law:

The vapour pressure of a volatile solute A is proportional to its mole fraction in a solution.

Mathematically, it can be represented as

$p_A=K_H^{\text{'}}{X}_A$

Where,

$K_H^{\text{'}}=$ Henry’s law constant

$X_A=$ Mole fraction of a volatile solute A

$p_A=$ Vapour pressure of a volatile solute A

$\boxed{X_A+X_B=1}$

(d)

Interpretation Introduction

Interpretation:

The interactions between acetone and chloroform in the liquid mixture has to be described.

Concept Introduction:

Ideal solution:

Ideal Solutions obey Raoult’s Law at every range of concentration and at all temperatures.

Non-ideal solution:

Non-ideal solutions don’t obey Raoult’s Law at every range of concentration and at all temperatures.

Non-ideal solutions are of two types.  One is showing positive deviation and another one is showing negative deviation from Raoult’s law.

Positive deviation from Raoult’s law:

This occurs when vapour pressure of the component is greater than what is expected in Raoult’s law.  So the solute-solvent forces of attraction are weaker than solute-solute and solvent-solvent interaction.

Negative deviation from Raoult’s law:

This occurs when total vapour pressure is less than what is expected in Raoult’s law.  So the solute-solvent forces of attraction are stronger than solute-solute and solvent-solvent interaction.