Question

Use LeChatelier’s Principle to explain why the solubility of a compound containing a basic anion (that is, the anion of a weak acid) increases as the solution becomes more acidic

Answer 1

Solution of a weak anion increases as acidity of the solution increases. This is according to the LeChatellier's principle which states that any change in the reaction at equilibrium would push the equilibrium to that direction so as to minize the change occured.

Thus when acidity increases, H+ ion concentration goes up, which combines with basic anion and reduces concentration of free basic anion in solution. Thus the reaction moves to a direction to increase the concentration of basic anion and reestablish equilibrium condition. So solubility goes up to increase this concentration of free basic anion in solution.