Imagine that you have a 0.00750 M aqueous MgCl2 solution, prepared so that it contains a small amount of radioactive 28Mg. The half-life of 28Mg is 20.91h, and the initial activity of the MgCl2 solution is 0.120 Ci/mL . Assume that 20.00 mL of this MgCl2 solution is added to 15.00 mL of 0.01250 M aqueous Na2CO3 solution and that the resultant precipitate is then removed by filtration to give a clear filtrate. After a long break to go for a run, you find that the activity of the filtrate measured 2.40 h after beginning the experiment is 2.9102 Ci/mL .

What is the molar concentration of Mg2+ ?

What is the molar concentration of CO23 in the filtrate?

What is the solubility product constant of MgCO3 ?