1. Electrolysis

2.  Running a galvanic cell backwards.  Put a voltage bigger than the cell potential on the wire and reverse the direction of the redox reaction.  The Cathode & Anode swap as well as the flow direction of the ions.  Used for electroplating. Electrolysis

3. 1.0 M Zn +2 e-e- e-e- Anode Cathode 1.10 Zn Cu 1.0 M Cu +2

4. 1.0 M Zn +2 e-e- e-e- Anode Cathode A battery >1.10V Zn Cu 1.0 M Cu +2

5. Draw the following cell….  2I - (ag) + Cu 2+ (ag)  I 2(s) + Cu (s)  Which process takes place at the anode? Cathode?  What are the electrodes made of?  What is the direction of electron flow? Is the reaction spontaneous?  What Voltage is necessary to force electrolysis?

6. Electroplating  Place a current on the system which is greater then the potential at which the metal ion is reduced.  The metal will plate out.  The amount of metal reduced is directly related to the current in Amps. Amps = Coulombs/sec  Not a perfectly efficient process.

7. Calculating plating  Use Stoichiometry to solve.  G  moles  moles of e-  coulombs  Current  time  How long must 6.00 amp current be applied to produce 15.5 g of Au from Au 3+ ?

8. Another Approach  An aqueous solution of Lead II chloride contains 927g of lead chloride. What current (in Amps) is necessary to remove all the lead from the solution in 48 hours?

9. Other uses  Electrolysis of water.  Separating mixtures of ions.  More positive reduction potential means the reaction proceeds forward forming products.  These need less current to reduce.  Most positive reduction potential is easiest to plate out of solution.

10. Predict the order of reduction for the following ions…  Ag +, Zn 2+, IO 3 -  Ag + + e-  Ag  Zn 2+ + 2 e-  Zn  IO 3 - +6H + + 5e -  ½ I 2 + 3H 2 O