The equation for the equilibrium is
and the solubility product expression is Ksp = [Ca2+] [SO42–] = 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 CaCl2 , so the concentration of Ca2+ ions is
= 8.33 × 10–3 M and the concentration of SO42– ions is
The ionic product is [Ca2+] [SO42–] = (8.33 × 10–3) (1.0 × 10–1) = 8.33 × 10–4
Which is larger than Ksp, so CaSO4 should precipitate from the solution.