Chapter 16, Problem 37PE

(a)

Interpretation Introduction

Interpretation:

The molar solubility of ${\text{CaF}}_2$ has to be determined.

Concept Introduction:

The equilibrium constant used for the partially soluble salt in water is termed as solubility product constant $K_{\text{sp}}$. Consider solubility of $\text{AB}$ in water and equilibrium equation of $\text{AB}$ is as follows:

  $\text{AB}\left(s\right)\rightleftharpoons {\text{A}}^{+}\left(aq\right)+{\text{B}}^{-}\left(aq\right)$

The expression for $K_{\text{sp}}$ is as follows:

  $K_{\text{sp}}=\frac{\left[{\text{A}}^{+}\right]\left[{\text{B}}^{-}\right]}{\left[\text{AB}\left(s\right)\right]}$

Generally the concentration of solid is taken as constant. Therefore the expression for $K_{\text{sp}}$ of $\text{AB}$ is as follows:

  $K_{\text{sp}}=\left[{\text{A}}^{+}\right]\left[{\text{B}}^{-}\right]$

(b)

Interpretation Introduction

Interpretation:

The molar solubility of $\text{Fe}{\left(\text{OH}\right)}_{\text{3}}$ has to be determined.

Concept Introduction:

Refer to part (a).