1. What does this?

2. Have to do with this? NOTHING!!!

3. B/ Electrolytic Cells: Electrolysis - when an electric current is used to force a redox reaction that is normally nonspontaneous to occur They convert electrical energy  chemical energy Like voltaic cells, electrolytic cells have: a. redox reactions involving electrons b. an anode where oxidation takes place because electrons are removed (lost) from there c. a cathode where reduction takes place because electrons are moved (gained) there d. electrons flowing from anode to cathode

4. battery + - Unlike voltaic cells, electrolytic cells have these differences: a. A battery or other source of electrical energy must be used because the reaction is nonspontaneous. b. The anode is now positive (+), and the cathode is now negative (-). This is the opposite of a voltaic cell. c. Both oxidation and reduction occur in the same cell. anodecathode e-e- + - Diagram of an electrolytic cell: e-e-

5. Uses of Electrolytic Cells: Ex. Electrolysis of molten salts to produce active metals: 2NaCl(l) +  2Na(l) + Cl(g) Oxidation at the anode: 2Cl -  Cl 2 + 2e - Reduction at the cathode:2Na + + 2e -  2Na electrical energy

7. Uses of Electrolytic Cells: Ex. Electrolysis of molten salts to produce active metals: 2NaCl(l) +  2Na(l) + Cl(g) Oxidation at the anode: 2Cl -  Cl 2 + 2e - Reduction at the cathode:2Na + + 2e -  2Na Ex. The electrolysis of water: 2H 2 O(l) +  2H 2 (g) + O 2 (g) Notice that twice as many hydrogen molecules as oxygen molecules are produced.  In both examples, electrical energy is a “reactant.” electrical energy electrical energy

8. The half reactions in the electrolysis of H 2 O are not as simple as other examples seen so far: At the anode: 2H 2 O  O 2 + 4H + + 4e - At the cathode: 4H + + 4e -  2H 2

10. Ex. Electroplating – During electrolysis, a layer of a second metal can be deposited on the metal cathode. The purpose is to: 1/ improve the appearance of objects 2/ protect them from corrosion. Silver bar is a source for plating the spoon. A steel spoon is the object to be plated.

11. At the silver bar, the neutral solid silver is oxidized: Ag(s)  Ag + + e - The electrons are attracted to the positive side of the battery. The Ag + ions enter solution and are attracted to the negative spoon.

12. Ex. Electroplating – During electrolysis, a layer of a second metal can be deposited on the metal cathode. The purpose is to: 1/ improve the appearance of objects 2/ protect them from corrosion. Silver bar is a source for plating the spoon. A steel spoon is the object to be plated.

13. At the silver bar, the neutral solid silver is oxidized: Ag(s)  Ag + + e - The electrons are attracted to the positive side of the battery. The Ag + ions enter solution and are attracted to the negative spoon. When they reach the steel spoon, the Ag + ions gain electrons that come from the negative side of the battery and are reduced to solid silver: Ag + + e -  Ag(s) This solid silver plates (covers) the steel spoon. The battery holds the anode at a positive potential and the cathode at a negative potential.  This is the opposite of a voltaic cell.

14. Ex. Electroplating – During electrolysis, a layer of a second metal can be deposited on the metal cathode. The purpose is to: 1/ improve the appearance of objects 2/ protect them from corrosion. Silver bar is a source for plating the spoon. A steel spoon is the object to be plated.