1. Lecture 92/09/05

2. Compare the solubility of AgCl in pure water at 25˚C and the solubility of AgCl in a solution of 0.55M NaCl? K sp = 1.8 x 10 -10 at 25˚C. AgBr (s) ↔ Ag + (aq) + Cl - (aq) I00 C+ X EXX

3. Compare the solubility of AgCl in pure water at 25˚C and the solubility of AgCl in a solution of 0.55M NaCl? K sp = 1.8 x 10 -10 at 25˚C. AgCl (s) ↔ Ag + (aq) + Cl - (aq) I00.55 M C+ X EX0.55 M + X How does X compare to 1.3 x 10 -5 M? Can ignore X for 0.55 + X since X << 0.55 M Always check assumption If > 2 orders of magnitude difference, good assumption

4. Formation of complex ions Metal ions can act as a Lewis acid (electron pair acceptor) Examples of Lewis bases NH 3 CN - S 2 O 3 2- SCN - Lewis acid + Lewis base  Complex Ion

5. Complex ions Ag + (aq) + 2NH 3 (aq) ↔ Ag(NH 3 ) 2 + (aq)

6. Complex ions and solubility AgCl (s) ↔ Ag + (aq) + Cl - (aq) Ag + (aq) + 2NH 3 (aq) ↔ Ag(NH 3 ) 2 + (aq) AgCl (s) + 2NH 3 (aq) ↔ Ag(NH 3 ) 2 + (aq) + Cl - (aq)

7. End of material for Exam 1