An excess of solid calcium fluoride is shaken with 0.100 M HCl until a saturated solution is obtained (pKa=3.17 for HCl; pKw=14.00) Assume all species behave ideally and that there is no ion-pairing.
Write the charge-balance as well as the mass-balance equations for the system (let s represent the solubility of the calcium fluoride). And solve the equilibrium problem to determine the solubility of the CaF2