Chapter 16, Problem 21RQ

Interpretation Introduction

Interpretation:

Relative order of molar solubility of $\text{AgCl}$, $\text{AgBr}$, $\text{AgI}$, ${\text{AgC}}_{\text{2}}{\text{H}}_{\text{3}}{\text{O}}_{\text{2}}$, ${\text{PbSO}}_{\text{4}}$, ${\text{BaSO}}_{\text{4}}$, ${\text{BaCrO}}_{\text{4}}$ and $\text{PbS}$ has to be arranged.

Concept Introduction:

Equilibrium constant for partially soluble salt is denoted by $K_{\text{sp}}$. It forms equilibrium between solids and its ions in a solution.  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:

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