The solubility of copper(II) hydroxide in water can be increased by adding either the base \(\mathrm{NH}_{3}\) or the acid \(\mathrm{HNO}_{3} .\) Explain. Would added \(\mathrm{NH}_{3}\) or \(\mathrm{HNO}_{3}\) have the same effect on the solubility of silver acetate or silver chloride? Explain.

: For copper(II) hydroxide, the dissociation equilibrium in water is given by: \[\mathrm{Cu(OH)_2 (s) \rightleftharpoons Cu^{2+} (aq) + 2OH^{-} (aq)}\] For silver acetate and silver chloride, the dissociation equilibria are given by: \[\mathrm{AgC_2H_3O_2 (s) \rightleftharpoons Ag^+ (aq) + C_2H_3O_2^{-} (aq)}\] \[\mathrm{AgCl (s) \rightleftharpoons Ag^+ (aq) + Cl^- (aq)}\]

: Let's look at the reaction of ammonia with water and the possible reaction of ammonia with Cu(II) in solution: \[\mathrm{NH_3 (aq) + H_2O (l) \rightleftharpoons NH_4^+ (aq) + OH^- (aq)}\] \[\mathrm{Cu^{2+} (aq) + 4NH_3 (aq) \rightleftharpoons [Cu(NH_3)_4]^{2+} (aq)}\] By Le Chatelier's principle, adding ammonia to the solution will shift the equilibria above to the right. This will increase the \(\mathrm{OH}^-\) and \(\mathrm{[Cu(NH_3)_4]^{2+}}\) concentrations, which causes the equilibrium of copper(II) hydroxide dissociation to shift to the right as well, increasing its solubility. The same increase in solubility would be observed for silver acetate due to the increase in \(\mathrm{OH}^-\) concentration in solution. For silver chloride, although the equilibrium would not be affected directly by \(\mathrm{NH_3}\).

: When nitric acid is added to the solution, it will react with any hydroxide ions in solution: \[\mathrm{HNO_3 (aq) + OH^- (aq) \rightleftharpoons NO_3^- (aq) + H_2O (l)}\] By removing the hydroxide ions, the equilibrium of copper(II) hydroxide dissociation will shift to the right, increasing its solubility. However, adding nitric acid will have a different effect on silver acetate and silver chloride solubility. The acetate ion can react with \(\mathrm{HNO_3}\), so the solubility of silver acetate might increase. The solubility of silver chloride would not be affected by \(\mathrm{HNO_3}\) as chloride ions do not react with nitric acid. In conclusion, adding \(\mathrm{NH_{3}}\) and \(\mathrm{HNO}_{3}\) increases the solubility of copper(II) hydroxide, but their effects on silver acetate and silver chloride solubility vary.