The table below lists solubility-product constants at 25 °C for three alkaline-earth carbonates.
Salt
Ksp
CaCO₃
4.8×10−9
SrCO₃
1.1×10−9
BaCO₃
5.0×10−9
A chemist prepares three separate beakers, each containing 500 mL of 0.10 M Na₂CO₃ at 25 °C. To each beaker, she adds sufficient solid carbonate (CaCO₃, SrCO₃, or BaCO₃) to establish equilibrium with its ions in the solution.
(a) For each carbonate salt, write the equilibrium expression corresponding to its dissolution in water.
(b) Calculate the equilibrium molar concentration of the metal cation in each beaker after equilibrium is reached.
(c) Rank the three salts in order of decreasing amount (in moles) of solid that ultimately dissolves in the 0.10 M Na₂CO₃ solution. Provide a clear justification that references your calculations in part (b).
(d) Explain why the ranking obtained in part (c) differs, if at all, from the ranking that would be observed for the molar solubility of the same salts in pure water.