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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.

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).
Cl-  -  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.

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