Consider three sparingly soluble salts at 25 °C: iron(II) sulfide (FeS)
CHEMISTRY · Multi-part · AP · Chemistry · Acids and Bases · Acids and Bases
Problem
Consider three sparingly soluble salts at 25 °C: iron(II) sulfide (FeS), calcium fluoride (CaF2), and silver chloride (AgCl).
(a) For each salt, state qualitatively (increase, decrease, or approximately no change) how its molar solubility will respond to a substantial decrease in pH. Justify each prediction in terms of the chemical species present in solution.
(b) Rank the three salts in order of increasing sensitivity of solubility to pH change, providing a clear rationale for your ordering.
(c) Using FeS as an example, sketch a qualitative graph of molar solubility (vertical axis) versus pH (horizontal axis) over the range pH 0–14. Label key features of the curve and explain their chemical significance.