Chapter 16, Problem 98AE

In the chapter discussion of precipitate formation, we ran the precipitation reaction to completion and then let some of the precipitate redissolve to get back to equilibrium. To see why, redo Example 15-6, where

Initial Cocentration (mol/L)	Equilibrium Concentration (mol)/L
[Mg2+]0 = 3.75 × 10−3 [F−]0 = 6.25 × 10−2 $\underset{\begin{array}{l}\text{reacts}\text{to}\\ \text{form}{\text{MgF}}_2\end{array}}{\overset{\text{y}{\text{mol/Mg}}^{\text{2+}}}{\to }}$	[Mg2+] = 3.75 × 10−3 − y [F−] = 6.25 × 10−2 – 2y