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Question
In order to obtain 1 tonne of aluminium, the following inputs are required: 4 tonnes of bauxite, 150 kg of sodium hydroxide and 600 kg of graphite. The aluminium compound in bauxite is aluminium oxide and the main impurity is iron (III) oxide. Aluminium is obtained by the electrolysis of aluminium oxide dissolved in cryolite.
- Name the process used for the purification of bauxite.
- Write the equation for the action of heat on aluminium hydroxide.
Solution
- The process used for the purification of bauxite is Baeyer's process.
- The action of heat on aluminium hydroxide:
\[\ce{2Al(OH)3 ->[heat][1000^\circ C]Al2O3 + 3H2O}\]
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Identify the components of the electrolyte other than pure alumina and the role played by each
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Give reason for the following:
Aluminium oxide cannot be reduced by carbon.
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Bauxite is the main ore of aluminium.
