IB Chemistry Power Points Topic 09 Electrolytic Cells SLwww.pedagogics.ca
Electrolytic Cellsan electric current is used to drive a non-spontaneous redox reaction This process is called electrolysis
Electric current enters and exits the cell by electrodesElectrolytic cells often use inert electrodes (electrodes thatdon’t react).Like voltaic cells:1. Cathode: - electrode at which reduction occurs2. Anode: - electrode at which oxidation occurs Unlike voltaic cells: cathode is (-) & anode is (+) Electrodes are immersed in a common electrolyte.
Cathode is the negative terminal of the power supply This is the site of reduction of +ive ions in electrolyte Negative ions are oxidized at the anode.Electrolytic cells are used for extraction, refining,electroplating, commercial manufacture of gases, etc.
Predicting electrolysis productsMolten Salt ElectrolytesREQUIRES – molten salt and inert electrodesALWAYS – metal cation reduced at cathode, nonmetal anionoxidized at anode.Write the cathode, anode and overall rxns for this example Pb2+ (l) + 2e- Pb (l) 2Br- (l) Br2 (g) + 2e- Pb2+ (l) + 2Br- (l) Pb (l) + Br2 (g)