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InterviewSolution
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Describe the process of electronlytic reduction of Alumina with the help of a diagram. |
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Answer» (i) During the process of electrolytic reduction of aliminium,a molten mixture of pure alumina (m.p is `gt 2000^@)C)` is electrolyedin a steel tank. (ii) This tan is lined inside with carbon graphite which acts as cathode and a set of graphite rods dipped in the molten electrolyte act as anode. (iii) Cryolite `(Na_(3)AlF_(6))` and fluorspar `(CaF_(6))` are also added to the mixutre to lower the metling point about `100^(@)C`. Current is passed through the electrolyte and aluminum is formedat the cathode. (iv) The molten aliminium sinks to the bottome of the tank as itis heavier from there it is removed perodically. (v) Oxygen in liberated at the anode. (vi) The reaction occuring atthe cathode and anode are : Cathode reaction `Al^(3+)+3e^(-) to Al_((l))` (Reduction) Anode reaction `2O^(2+)+ 4e^(-) to O_(2) 4e^(-)` (Oxidation) (vii) The oxygen liberated react with the carbon anode to form carbon dioxide gas. (viii) As a results of this oxidation, carbon anode have to be replaced at intervals. |
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