Chapter 19, Problem 19.7P

(a)

Interpretation Introduction

Interpretation:

The ${\text{K}}_{\text{p}}$ expression for the equation ${\text{SO}}_{\text{2}}{\text{Cl}}_{\text{2(g)}}\rightleftharpoons {\text{ SO}}_{\text{2}}{}_{\text{(g)}}{\text{ + Cl}}_{\text{2(g)}}$ has to be written and also the unit of ${\text{K}}_{\text{p}}$ has to be given.

Concept Introduction:

Equilibrium constant$\left({\text{K}}_{\text{p}}\right)$:

In gas phase reactions, partial pressure is used to write equilibrium equation than molar concentration. Equilibrium constant $\left({\text{K}}_{\text{p}}\right)$ is defined as ratio of partial pressure of products to partial pressure of reactants. Each partial pressure term is raised to a power, which is same as the coefficients in the chemical reaction.

Consider the reaction where A reacts to give B.

    $\text{aA}\rightleftharpoons \text{bB}$

    $\begin{array}{l}\text{Rate of forward reaction = Rate of reverse reaction}\\ {\text{k}}_{\text{f}}{\text{P}}_{\text{A}}{}^{\text{a}}{\text{=k}}_{\text{r}}{\text{P}}_{\text{B}}{}^{\text{a}}\end{array}$

On rearranging,

    $\frac{{\text{P}}_{\text{B}}{}^{\text{b}}}{{\text{P}}_{\text{A}}{}^{\text{a}}}\text{=}\frac{{\text{k}}_{\text{f}}}{{\text{k}}_{\text{r}}}{\text{= K}}_{\text{p}}$

Where,

    ${\text{k}}_{\text{f}}$ is the rate constant of the forward reaction.

    ${\text{k}}_{\text{r}}$ is the rate constant of the reverse reaction.

    ${\text{K}}_{\text{p}}$ is the equilibrium constant

The solids and pure liquids are not involved in equilibrium constant expression.

(b)

Interpretation Introduction

Interpretation:

The equilibrium constant expression, ${\text{K}}_{\text{p}}$ for the equation ${\text{2H}}_{\text{2}}{\text{O}}_{\text{2(g)}}\rightleftharpoons {\text{ 2H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{ + O}}_{\text{2(g)}}$ has to be written and also the unit of ${\text{K}}_{\text{p}}$ has to be given.

Concept Introduction:

Refer part (a)

(c)

Interpretation Introduction

Interpretation:

The equilibrium constant expression, ${\text{K}}_{\text{p}}$ for the equation ${\text{2CaSO}}_{\text{4}}·{\text{H}}_{\text{2}}{\text{O}}_{\text{(s)}}{\text{ + 2H}}_{\text{2}}{\text{O}}_{\text{(g)}}\rightleftharpoons 2{\text{CaSO}}_{\text{4}}·{\text{2H}}_{\text{2}}{\text{O}}_{\text{(s)}}$ has to be written and also the unit of ${\text{K}}_{\text{p}}$ has to be given.

Concept Introduction:

Refer part (a).