2. Common-Ion EffectCommon-Ion Effect  Similar to acids and bases  There is a “common ion” when 2 salt solutions are mixed together.

3. Example 1:Example 1:  Ag 2 SO 4(s)  2Ag + (aq) + SO 4 -2 (aq)  What happens if Na 2 SO 4 is added to the solution?

4. Example 2:Example 2:  Ag 2 SO 4(s)  2Ag + (aq) + SO 4 -2 (aq)  What happens when AgNO 3 is added to the solution?

5. **Any time a common ion is formed through a second solute, the slightly ionic compound has LESS solubility!!**

6. Example 3:Example 3:  Calculate the molar solubility of Ag 2 SO 4 in 1.00M Na 2 SO 4(aq)

7. Example 4:Example 4:  What is the molar solubility of silver carbonate in a 0.85M solution of potassium carbonate?

8. Example 5:Example 5:  The solubility of a 250.0 ml saturated solution of Ag 2 SO 4(aq) is reduced to 1.0x10 -3 M. How many grams of silver nitrate must be added to this solution to cause that solubility reduction? (Ksp = 1.4 x 10 -5 )

9. Example 6:Example 6:  What is the molar solubility of aluminum hydroxide in a solution with a pH = 12.37?

10. What happens if other ions are present in the solution but are not “common ions”?  CaF 2  Ca +2 + 2F -  With pure water Ksp = 2.15 x 10 -4  With 0.010M Na 2 SO 4 Ksp = 3 x 10 -4  CaF 2 is more soluble, may be because no common ions but why 50% increase????

11. What happens if other ions are present in the solution but are not “common ions”?  Na 2 SO 4 ions interact with CaF 2 ions and prevent them from recombining to form CaF 2  More anions surrounding Ca +2 than in water.  More cations surrounding F - than in water.  More solubility than in water where no hindrance exists.

12. Ionic Compounds in Aqueous Solutions  Think of them having 2 concentrations. 1)Ksp/solute amount in solution  Based on stoichiometry 2)Activity  Based on interionic attractions occurring in a solution  How ion attractions affect solute amount in solution