Unit 8: Electrochemistry Applications Lesson 7: Applied Electrolysis

Electroplating Electroplating is an electrolytic process in which a metal is reduced or “plated out” at a cathode. The cathode is the material to be plated. The electroplating solution contains ions of the metal to be “plated” onto the cathode. The anode is either inert or the same metal to be “plated” onto the cathode.

Example Design a cell to electroplate a copper medallion with nickel. Include the ions present in solution, the substances used for the anode and cathode, and the direction of electron and ion flow. 10 min

Brain Break! Spot It!

(contains impurities such as Zn, Pb, Ag, Au, Pt) Electrorefining Electrorefining is the process of purifying a metal by electrolysis. E.g. (contains impurities such as Zn, Pb, Ag, Au, Pt)

At the Anode The small amounts of Zn and Pb are oxidized first and go into solution as ions. Cu is oxidized next and also goes into solution as ions. Since the anode is mostly Cu, the Au, Ag, and Pt impurities will not be oxidized but will just drop off the anode and sink to the bottom of the cell.

At the Cathode The Cu2+ in solution is preferentially reduced, and the other ions stay in solution. This results in the pure Cu cathode gathering more and more pure Cu! (This process works for other metals as well, including Pb, Sn, and Ni.)

Homework Pg. 244 #75-76 Pg. 246 #77 10 min