Chapter 17, Problem 73A

Interpretation Introduction

Interpretation:

Whether a precipitate will form or not needs to be explained.

Concept introduction:

Out of two competing solutes in a solution the solute with lower K_sp will precipitate.

Answer to Problem 73A

No precipitate will form in the solution.

Explanation of Solution

Total volume of mixture

$\begin{array}{l}=62.6+31.3=93.9mL\\ =0.0939L\end{array}$

Given the K_spof Ca(OH)₂=5 $\times$ 10-6

In the above solution,

$\begin{array}{l}[C{a}^{2+}]=\frac{0.0626\times 0.0322}{0.0939}=0.0215M\\ [O{H}^{-}]=\frac{0.0313\times 0.0145}{0.0939}=4.83\times {10}^{-7}M\\ \text{Equation for solution of calcium hydroxide,}\\ Ca{(}_O\stackrel{}{\rightleftarrows }C{a}^{2+}+2O{H}^{-}\\ Q_{sp}=[C{a}^{2+}]{[}^O\\ Q_{sp}=5\times {10}^{-7}\end{array}$

Q_sp is less than K_sp so precipitate will not form.

Conclusion

The reason for no precipitate formation has been explained.