Chapter 18, Problem 108SAE

Interpretation Introduction

Interpretation:

The soluble solid in NH₃ should be determined.

Concept introduction:

A complex ion is a polyatomic cation or anion composed of a central metal ion to which other groups (molecules or ions) called ligands are bonded. Coordination compounds are substances containing complex ions.

To describe the ionization of a weak acid, we use the ionization constant for a solubility equilibrium, we use the solubility product constant K_sp. The equilibrium constant that is used to deal with complex-ion equilibrium is called the formation constant. The formation constant, K_f, of a complex ion is the equilibrium constant describing the formation of a complex ion from a central ion and its attached groups.

$\begin{array}{l}{\text{Cu}}^{\text{2+}}{\text{(aq) +4NH}}_{\text{3}}\text{(aq)}\rightleftharpoons {\left[Cu{\left(N{H}_3\right)}_4\right]}^{2+}\text{(aq)}\\ \\ K_f=\frac{\left[{\left[Cu{\left(N{H}_3\right)}_4\right]}^{2+}\text{(aq)}\right]}{\left[{\text{Cu}}^{\text{2+}}\text{(aq) }\right]{\left[{\text{NH}}_{\text{3}}\text{(aq)}\right]}^4}\end{array}$