Chapter 14, Problem 14.84QE

(a)

Interpretation Introduction

Interpretation:

Whether aluminium phosphate or calcium phosphate begins to precipitate should be determined.

Concept Introduction:

Solubility product is the equilibrium constant for the reaction that occurs when an ionic compound is dissolved to produce its constituent ions. It is represented by $K_{\text{sp}}$. Consider ${\text{A}}_x{\text{B}}_y$ to be an ionic compound. Its dissociation occurs as follows:

  ${\text{A}}_x{\text{B}}_y\rightleftharpoons x{\text{A}}^{y+}+y{\text{A}}^{x-}$

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

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

(b)

Interpretation Introduction

Interpretation:

As the second species begins to precipitate, the concentration of the first species has to be determined.

Concept Introduction:

Refer to part (a).