The equation for the equilibrium is

and the solubility product expression is K_{sp} = [Ca^{2+}] [SO_{4}^{2–}] = 2.4 × 10^{–5}

If we assume that the volumes of the solutions that are mixed are additive, the final solution will have a volume of 600 ml. This total volume contains the equivalent of 200 mL of CaCl_{2} , so the concentration of Ca^{2+} ions is

= 8.33 × 10^{–3} M and the concentration of SO_{4}^{2–} ions is

The ionic product is [Ca^{2+}] [SO_{4}^{2–}] = (8.33 × 10^{–3}) (1.0 × 10^{–1}) = 8.33 × 10^{–4}

Which is larger than K_{sp}, so CaSO_{4} should precipitate from the solution.