How is aluminium metal extracted? Explain with the help of an equation.
Aluminium is extracted by electrolytic reduction of its molten oxide. Aluminium is a highly reactive metal and it is placed at the top of the reactivity series. This cannot be reduced by other reducing agents such as coke, carbon monoxide etc.
On passing electricity through molten aluminium oxide, decomposition reaction occurs and formation of aluminium metal and oxygen gas takes place.
Molten aluminium oxide consists of aluminium and oxide ions. The reactions that occur during electrolysis are:
1. Cathode produces electrons to reduce aluminium ions to aluminium atoms (or aluminium metal) by acting as reducing agent. Aluminium ions are cations; therefore, they get attracted to negatively charged cathode and get deposited there.
xide ions are anions; therefore, they get attracted to positively charged anode. These oxide ions are oxidised to oxygen gas. Oxygen gas is produced at anode.
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