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प्रश्न
In the Hall's process for extraction of aluminium, Give the formula and purpose of fluorspar and cryolite
उत्तर
Fluorspar is CaF2 and it helps in the mobility of the fused mixture.
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संबंधित प्रश्न
For the substance given below, describe the role played in the extraction of aluminium.
Sodium hydroxide
For bauxite, explain its significance in the extraction of aluminium.
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.
When bauxite is treated with sodium hydroxide solution, what happens to:
- the aluminium oxide,
- the iron (III) oxide?
Give reason for the following:
Aluminium oxide cannot be reduced by carbon.
The following question relate to the extraction of aluminium by electrolysis.
Explain why is it necessary to renew the anode periodically.
Write the equation for the reaction where the aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide.
Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.
Write the equation for the reaction that occurs at the cathode during the extraction by aluminium by electrolysis.
Explain with reason:
A neutral gas other than oxygen is formed at the anode during the electrolysis of fused alumina.
State the relevant reason for the following:
A layer of powered coke is used over the electrolytic mixture in Hall Heroult’s process.
