Chapter 17.3, Problem 25PP

a.

Interpretation Introduction

Interpretation:

Whether precipitate of PbF₂ will form or not needs to be predicted.

Concept introduction:

When the Q_sp becomes greater than the solubility product, a precipitate will form.

Answer to Problem 25PP

A precipitate will form.

Explanation of Solution

When the above solutions are mixed, PbF₂ will form.

Its $K_{sp}=3.3\times {10}^{-8}$

Now for the solution,

$\begin{array}{l}{Q}_{sp}=[P{b}^{2+}]{[}^{F^{-}}\\ Q_{sp}=0.1\times {0.03}^2\\ Q_{sp}=1.1\times {10}^{-5}\end{array}$

Which is greater than the K_sp so precipitate will form.

b.

Interpretation Introduction

Interpretation:

Whether precipitate of Ag₂SO₄will form or not needs to be predicted.

Concept introduction:

When the Q_sp becomes greater than the solubility product, a precipitate will form.

Answer to Problem 25PP

A precipitate will not form.

Explanation of Solution

When the above solutions are mixed, Ag₂SO₄will form.

Its $K_{sp}=1.2\times {10}^{-5}$

Now for the solution,

$\begin{array}{l}{Q}_{sp}={[}^A[S{O}_4{}^{2-}]\\ Q_{sp}={0.005}^2\times 0.125\\ Q_{sp}=3.1\times {10}^{-6}\end{array}$

Which is less than the K_sp so no precipitate will form.