Chapter 12, Problem 12.4P

(a)

Interpretation Introduction

Interpretation:

Whether a decrease in activity coefficient observed due to increase in ionic strength is true statement or not has to be identified.

Concept Introduction:

For equilibrium as indicated below,

  $a\text{A}+b\text{B}\rightleftharpoons c\text{C}+d\text{D}$

Law of mass action states that for such equilibrium that involves solutions and gases expression of equilibrium constant in principle is written in accordance with law of mass action as follows:

  $K=\frac{{\left[\text{C}\right]}^c{\left[\text{D}\right]}^d}{{\left[\text{A}\right]}^a{\left[\text{B}\right]}^b}$

Here,

$\left[\text{C}\right]$ denotes equilibrium concentration of C.

$\left[\text{D}\right]$ denotes equilibrium concentration of D.

$\left[\text{A}\right]$ denotes equilibrium concentration of A.

$\left[\text{B}\right]$ denotes equilibrium concentration of B.

$K$ denotes equilibrium constant.

$a$, $b$, $c$ and $d$ are stoichiometric coefficients.

To account for changed ionic atmosphere of various species concentration terms are include concept of activities. Activity is defined as product of concentration times the activity coefficient. Thus expression of equilibrium constant is then written as follows:

  $K=\frac{{\left[\text{C}\right]}^c{\text{γ}}_{\text{C}}^c{\left[\text{D}\right]}^d{\text{γ}}_{\text{D}}^d}{{\left[\text{A}\right]}^a{\text{γ}}_{\text{A}}^a{\left[\text{B}\right]}^b{\text{γ}}_{\text{B}}^b}$

(b)

Interpretation Introduction

Interpretation:

Whether a decrease in activity coefficient observed due to increase in ionic charge is true statement or not has to be identified.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Whether a decrease in activity coefficient observed due to decrease in hydrated size is true statement or not has to be identified.

Concept Introduction:

Refer to part (a).