Same chapter3 marksDifficulty: Medium
Name the process by which aluminium oxide is obtained pure from bauxite, and write the equations for the two main steps.
Metallurgy
3 marksDifficulty: Medium
In the electrolytic extraction of aluminium, state the role of cryolite and write the reactions at the electrodes.
Original Khojo Papers practice question — not from a past board paper.
Answer
Cryolite is added to lower the melting point of alumina from about 2050 °C to about 950 °C and to increase the conductivity of the melt. At the cathode Al3+ + 3e− → Al and at the anode 2O2− → O2 + 4e−.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The carbon anodes are burnt away by the oxygen liberated and have to be replaced periodically.
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