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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.

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^-       2K (potassium metal at the (-)cathode).
2Cl^-  -  2e^-       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)           2K_(s)  +   Cl_2(g)

See some other examples of electrolysis.

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