Extraction of Metals

Electrolysis of Potassium Chloride.

Potassium chloride must be heated until it is molten
before it will conduct electricity.
Electrolysis separates the molten ionic compound into its elements.

Electrolysis of Potassium Chloride

The reactions at each electrode are called half equations.
The half equations are written so that the same number of electrons
occur in each equation.

2K+  +  2e-    arrow   2K (potassium metal at the (-)cathode).
2Cl-  -  2e-    arrow   Cl2 (chlorine gas at the (+)anode).

Potassium ions gain electrons (reduction) to form potassium atoms.
Chloride ions lose electrons (oxidation) to form chlorine atoms.
The chlorine atoms combine to form molecules of chlorine gas.

The overall reaction is

2K+Cl-(l)      arrow     2K(s)  +   Cl2(g)

See some other examples of electrolysis.

back         Links        Electrolysis        Revision Questions        next

gcsescience.com      The Periodic Table      Index      Metal Quiz      gcsescience.com

Home      GCSE Chemistry      GCSE Physics

Copyright © 2014 Dr. Colin France. All Rights Reserved.