What general condition must be met for the pH of a solution to significantly alter a salt's solubility?
Answer
At least one ion produced upon dissolution must be capable of acting as an acid or base in water.
The influence of pH is rooted in acid-base reactions that couple with the dissolution equilibrium. If neither the cation nor the anion reacts significantly with excess $ ext{H}^+$ or $ ext{OH}^-$ ions, the solubility remains independent of the solution's pH.

Related Questions
What general condition must be met for the pH of a solution to significantly alter a salt's solubility?How is the solubility of sodium chloride ($ ext{NaCl}$) affected by changes in the solution's $ ext{pH}$?When acid ($ ext{H}^+$) is added to calcium fluoride ($ ext{CaF}_2$), what primarily happens to the fluoride ions ($ ext{F}^-$)?For a salt containing an anion that is the conjugate base of a weak acid, what drives increased dissolution upon lowering the $ ext{pH}$?In a basic solution, how does the solubility of ammonium chloride ($ ext{NH}_4 ext{Cl}$) increase?What characteristic describes the solubility curve of metal hydroxides that exhibit amphoterism when solubility is plotted against $ ext{pH}$?Which metal hydroxides are explicitly named as common examples of amphoteric substances?At low $ ext{pH}$, how does the dissolution of an amphoteric hydroxide like $ ext{Al}( ext{OH})_3$ proceed?What is the mechanism causing increased solubility of amphoteric hydroxides in highly basic solutions (high $ ext{pH}$)?If $ ext{Salt A}$ ($ ext{MCl}$) and $ ext{Salt B}$ ($ ext{MF}$) share the same $K_{sp}$, how does their solubility compare in an acidic $ ext{pH}$ environment?