Science, Tech, Math › Science Solubility Product From Solubility Example Problem Share Flipboard Email Print Science Chemistry Basics Chemical Laws Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Todd Helmenstine Todd Helmenstine is a science writer and illustrator who has taught physics and math at the college level. He holds bachelor's degrees in both physics and mathematics. our editorial process Todd Helmenstine Updated February 27, 2019 This example problem demonstrates how to determine the solubility product of an ionic solid in water from a substance's solubility. Problem The solubility of silver chloride, AgCl, is 1.26 x 10-5 M at 25 °C.The solubility of barium fluoride, BaF2, is 3.15 x 10-3 M at 25 °C.Calculate the solubility product, Ksp, of both compounds. Solution The key to solving solubility problems is to properly set up your dissociation reactions and define solubility. AgCl The dissociation reaction of AgCl in water isAgCl (s) ↔ Ag+ (aq) + Cl- (aq)For this reaction, each mole of AgCl that dissolves produces 1 mole of both Ag+ and Cl-. The solubility would then equal the concentration of either the Ag or Cl ions.solubility = [Ag+] = [Cl-]1.26 x 10-5 M = [Ag+] = [Cl-]Ksp = [Ag+][Cl-]Ksp = (1.26 x 10-5)(1.26 x 10-5)Ksp = 1.6 x 10-10 BaF2 The dissociation reaction of BaF2 in water isBaF2 (s) ↔ Ba+ (aq) + 2 F- (aq)This reaction shows that for every mole of BaF2 that dissolves, 1 mole of Ba+ and 2 moles of F- are formed. The solubility is equal to the concentration of the Ba ions in solution.solubility = [Ba+] = 7.94 x 10-3 M[F-] = 2 [Ba+]Ksp = [Ba+][F-]2Ksp = ([Ba+])(2 [Ba+])2Ksp = 4[Ba+]3Ksp = 4(7.94 x 10-3 M)3Ksp = 4(5 x 10-7)Ksp = 2 x 10-6 Answer The solubility product of AgCl is 1.6 x 10-10.The solubility product of BaF2 is 2 x 10-6.