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Extraction of Metals

Electrolysis of Magnesium Chloride.

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

The half equations are

Mg²⁺  +  2e^-       Mg (magnesium metal at the (-)cathode).
2Cl^-  -  2e^-       Cl₂ (chlorine gas at the (+)anode).

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

The overall reaction is

MgCl_2(l)           Mg_(s)  +   Cl_2(g)

See some other examples of electrolysis.

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