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Extraction of Metals

Electrolysis of Lead Bromide.

Lead bromide 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.

Pb²⁺  +  2e^-       Pb (lead metal at the (-)cathode).
2Br^-  -  2e^-       Br₂ (bromine gas at the (+)anode).

Lead ions gain electrons (reduction) to form lead atoms.
Bromide ions lose electrons (oxidation) to form bromine atoms.
The bromine atoms combine to form molecules of bromine gas.

The overall reaction is

PbBr_2(l)           Pb_(s)  +   Br_2(g)

See some other examples of electrolysis.

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