Which of the following salts will be substantially more soluble in acidic solution than in pure water? Briefly explain your answers. ZnCO3, ZnS, BiI3, AgCN, Ba3(PO4)2

Question

Which of the following salts will be substantially more soluble in acidic solution than in pure water? Briefly explain your answers.

ZnCO₃, ZnS, BiI₃, AgCN, Ba₃(PO₄)₂

Answer 1

ZnCO₃, ZnS, AgCN, Ba₃(PO₄)₂

The explanation is based on Le Chatelier's principle. If the anion of the salt is from a weak acid, the salt should be more soluble in acid because the formation of the weak acid will pull the equilibrium to the left. The formation of the weak acid (does not dissociate) essentially removes the anion from solution, thus increasing the solubility of the salt.

CO3^2- + H2O ==> 2OH^- + HCO3^-

S^2- + H2O ==> OH- + HS^-

CN^- + H2O ==> OH- + HCN

PO4^3- + H2O ==> HPO₄^2- + OH-