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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.

Electrolysis of Lead Bromide

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-    arrow   Pb (lead metal at the (-)cathode).
2Br-  -  2e-    arrow   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

PbBr2(l)      arrow     Pb(s)  +   Br2(g)

See some other examples of electrolysis.

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