Final answer:
To calculate the minimum pH needed to precipitate CaC2O4 from a 0.1000-M (NH4)2C2O4 solution, we need to consider the solubility product constant (Ksp) of CaC2O4. The minimum pH is determined by the concentration of C2O42- ions.
Step-by-step explanation:
To calculate the minimum pH needed to precipitate CaC2O4 from a 0.1000-M (NH4)2C2O4 solution, we need to consider the solubility product constant (Ksp) of CaC2O4. The Ksp expression for CaC2O4 is:
CaC2O4 (s) → Ca2+ (aq) + C2O42- (aq)
The Ksp value for CaC2O4 is 6.4 x 10^-9. At equilibrium, the product of the concentrations of Ca2+ and C2O42- is equal to the Ksp value. Therefore, the minimum pH needed to precipitate CaC2O4 is determined by the concentration of C2O42-. We can calculate the concentration of C2O42- using the solubility expression and then calculate the pH from the concentration of H+ ions.
The primary topic of this question is solubility and precipitation.