86. Solving a chemistry problem

The resistivity of a saturated solution of sparingly soluble salt A at 298 K is r. The specific resistance of water at the same temperature is rH2O = 1 • 104 Ohm • m. Calculate: 1) the solubility of salt A in pure water; 2) the product of the solubility of substance A, assuming that the activity coefficients of ions γ± = 1 (solutions are highly diluted); 3) the solubility of substance A in a solution containing 0.01 mol of substance B; 4) the solubility of substance A in a solution containing 0.01 mol of substance C. Substances A, B, C are completely dissociated.
r • 10-4, Ohm•m Substance A B C
0.0141 SrC2O4 H2C2O4 Na2SO4