A 1.0 × 10^{−3}\ M\ NaIO_{3}(aq) solution is made 0.010 M in Cu^{2+}(aq) by dissolving the soluble salt Cu(ClO_{4})_{2}(s). Does Cu(IO_{3})_{2}(s) (K_{sp} = 7.4 × 10^{−8}\ M^3) precipitate from the solution at 25°C?
The chemical equation for the solubility equilibrium is
Cu(IO_{3})_{2}(s) ⇋ Cu^{2+}(aq) + 2\ IO_{3}^−(aq)The value of Q_{sp} is
Q_{sp} = [Cu^{2+}]_{0}[IO_{3}^−]^{2}_{0} = (0.010\ M)(1.0 × 10^{−3}\ M)^2 = 1.0 × 10^{−8}\ M^3Because Q_{sp} \lt K_{sp}, no precipitate of Cu(IO_{3})_{2}(s) forms.