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Extraction Of Metals
For each of the substance listed below. Describe the role played in the extraction of aluminium.
(1) Cryolite:
(2) sodium hydroxide
(3) Graphite
(1) Cryolite: to reduce the melting point of alumina and increase the conductivity of the solution.
(2) sodium hydroxide: for purification of bauxite ore as a leaching agent.
(3) Graphite: As anode and make the reduction of Al2O3 easier.
Explain why:
(1) In the electrolysis of alumina using the Hall Heroult’s process the electrolyte.
(2) Iron sheets are coated with zinc during galvanization.
1) An electrolyte is covered with powdered coke to prevent heat loss from the molten electrolyte.
2) Iron sheets are coated with zinc by galvanisation to prevent rusting of iron sheets.
Choose the correct answer from the option given below:
The main ore used for the extraction of iron is :
-
Haematite
-
Calamine
-
Bauxite
-
Cryolite
A.
Haematite
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as:
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Smelting
-
Ore dressing
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Calcination
-
Bessemerisation
C.
Calcination
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Mock Test Series
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