1. Factors Affecting Solubility pH Common Ion Effect Formation of Complex Ions

2. Common Ion Effect If one of the ions in a solution equilibrium is already dissolved in the solution, the equilibrium will shift to the left and the solubility of the salt will decrease. BaSO 4 (s) Ba 2+ (aq) + SO 4 2− (aq)

3. Common Ion Effect Example Calculate the solubility of solid CaF 2 (Ksp = 4 x 10 -11 ) in a 0.025 M NaF solution. CaF 2 (s)  Ca +2 + 2 F - K sp = 4 x 10 -11 = [Ca +2 ] [ F - ] 2

4. pH –If a substance has a basic anion, it will be more soluble in an acidic solution. Cl-, I-, Br- –Substances with acidic cations are more soluble in basic solutions.

5. pH Example What is the effect of adding a strong acid on the solubility of silver acetate? 1.Silver acetate dissolves: AgC 2 H 3 O 2 (s)  Ag + (aq) + C 2 H 3 O 2 - (aq) 2.Acetate ion combines with H + (aq) ions from strong acid: H + (aq) + C 2 H 3 O 2 - (aq)  HC 2 H 3 O 2 (aq) [Acetate ion] is lowered by adding strong acid to form a weak acid. According to Le Chatelier's principle, the solubility equilibrium will shift to the right, causing more silver acetate to dissolve.

6. Complex Ions Question: What is a complex ion? Answer: A metal ion surrounded by ligands –Metal ions can act as Lewis acids and form complex ions with Lewis bases in the solvent.

7. More Complex Ions Ligand = Lewis Base, has lone pair that can be donated to empty orbital on metal to form a covalent bond Coordination Number(s) of 6,4,2 are most common.

8. Complex Ions –The formation of these complex ions increases the solubility of these salts.

9. Amphoterism –Amphoteric metal oxides and hydroxides are soluble in strong acid or base, because they can act either as acids or bases. –Examples of such cations are Al 3+, Zn 2+, and Sn 2+.