Final answer:
The question requires calculating ion concentrations at the point of saturation for precipitation using the solubility product constant (Ksp). The aim is to precipitate 99% of Ca2+ as CaSO4 without precipitating Ag+ as Ag2SO4 and to determine the remaining concentration of Ca2+ when Ag2SO4 starts to precipitate.
Step-by-step explanation:
The question is asking whether 99% of Ca2+ can be precipitated by sulfate without precipitating Ag+, and to find the concentration of Ca2+ when Ag2SO4 begins to precipitate. This involves understanding the solubility product constant (Ksp) and how to calculate the ion concentration at the point of saturation, where a salt will start to precipitate.
To answer this, we need the Ksp values for both CaSO4 and Ag2SO4. Let's assume these Ksp values are known to us. To prevent the precipitation of Ag+, the concentration of sulfate ions must be kept below the point where the ion product ([Ag+]2][SO42-]) exceeds the Ksp of Ag2SO4. To calculate at what concentration of Ca2+ the Ag2SO4 begins to precipitate, the concentration of sulfate ions that brings the ion product of Ca2+ and SO42- just below CaSO4's Ksp while also reaching the Ksp of Ag2SO4 would need to be determined. Once this sulfate concentration is found, one can calculate the remaining concentration of Ca2+ using the stoichiometry of the reaction and the initial concentration of Ca2+.