Consider the dissociation of strong versus weak acids: HCl(aq)+H2O(l)→H3O+(aq)+Cl−(aq)HF(a q)+H2O(l)⇌H3O+(aq)+F−(aq) The first reaction is not reversible, but the second one is. So, only the conjugate of the weak acid, F−, can react with H3O+. Now consider the solubility of insoluble salts: AgCl(s)⇌Ag+(aq)+Cl−(aq)AgF(s)⇌Ag+(a q)+F−(aq) The addition of acid has no effect on silver chloride. But for the second reaction, H3O+ will react with F−, decreasing its concentration and driving the equilibrium to the right. Thus, salts that contain the conjugate of a weak acid become more soluble as the acidity of the solution increases.