Consider a solution that is 0.022 M in Ba^{2+} and 0.020 M in Ca^{2+}. If sodium sulfate is used to selectively precipitate one of teh cations while leaving the other in solution, which cation will precipitate first? What minimum concentartion of Na_{2}SO_{4} will trigger the precipitation oftthe cation that precipitates first? Barium sulfate Ksp = 1.07 x 10^{-10} and calcium sulfate Ksp = 7.1 x 10^{-5}