Examgyani Team
Asked: November 7, 20232023-11-07T01:33:17+05:30
2023-11-07T01:33:17+05:30In: Science
MCQ Questions for Class 6 Science Chapter 14 Water with Answers
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Answer:
Dissociation of alumina:
2Al2O3→4Al3++3O2-
The equation for the reaction that takes place at the cathode is as follows:
Al3++3e-→Al
Aluminium, which is formed in a molten state at the cathode, settles at the bottom of the cell. It is collected as and when it is formed. The aluminium obtained through this process is 99% pure.
(b) The reaction that takes place during the extraction of aluminium at the anode is:
O2-→O+2e-O+O→O2
Oxygen so produced reacts with the carbon anode and forms CO and CO2.
C+O2→CO2
Due to oxidation at the carbon anode, it gets used up. Hence, it is necessary to renew carbon rods periodically.