Which of the following salts will be substantially more soluble in acidic solution than in pure water: (a) ZnCO \(_{3}\) \(\mathbf{b} ) \mathrm{ZnS},(\mathbf{c}) \mathrm{BiI}_{3},(\mathbf{d}) \mathrm{AgCN},(\mathbf{e}) \mathrm{Ba}_{3}\left(\mathrm{PO}_{4}\right)_{2} ?\)

When salts dissolve in water, they dissociate into their respective ions. Let's write down the dissociation reactions for each salt: (a) \(ZnCO_3 \rightarrow Zn^{2+} + CO_3^{2-}\) (b) \(ZnS \rightarrow Zn^{2+} + S^{2-}\) (c) \(BiI_3 \rightarrow Bi^{3+} + 3I^-\) (d) \(AgCN \rightarrow Ag^+ + CN^-\) (e) \(Ba_3(PO_4)_2 \rightarrow 3Ba^{2+} + 2PO_4^{3-}\)

We need to consider the effect of H+ ions (from the acidic solution) on each dissociation reaction mentioned in Step 1. This will help us understand which salt will be more soluble in acidic solution than in pure water: (a) H+ ions will react with \(CO_3^{2-}\) to form \(HCO_3^-\) or \(H_2CO_3\), which will decrease the concentration of \(CO_3^{2-}\), shifting the equilibrium to the right and increasing the solubility of ZnCO3 in an acidic solution. (b) H+ ions will react with \(S^{2-}\) to form \(HS^-\) or \(H_2S\), which will decrease the concentration of \(S^{2-}\), shifting the equilibrium to the right and increasing the solubility of ZnS in an acidic solution. (c) H+ ions have no notable effect on the solubility of \(BiI_3\) in an acidic solution. (d) H+ ions will react with \(CN^-\) to form \(HCN\), which will decrease the concentration of \(CN^-\), shifting the equilibrium to the right and increasing the solubility of AgCN in an acidic solution. (e) H+ ions will react with \(PO_4^{3-}\) to form \(HPO_4^{2-}\), \(H_2PO_4^-\), or \(H_3PO_4\), which will decrease the concentration of \(PO_4^{3-}\), shifting the equilibrium to the right and increasing the solubility of \(Ba_3(PO_4)_2\) in an acidic solution.

Based on the analysis in Step 2, we can conclude that the following salts are substantially more soluble in acidic solution than in pure water: (a) \(ZnCO_3\) (b) \(ZnS\) (d) \(AgCN\) (e) \(Ba_3(PO_4)_2\) The salt (c) \(BiI_3\) is not notably affected by the presence of the acidic solution. Thus, the answer should include salts (a), (b), (d), and (e).