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प्रश्न
What is the role of cryolite (NaAlF6) in the electrolytic reduction of alumina in the Hall's process?
उत्तर
Cryolite acts as a solvent for the electrolytic mixture in the electrolytic reduction of alumina in the Hall's process.
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संबंधित प्रश्न
Explain with reason:
Carbon can reduce lead oxide but not aluminium oxide.
Name three alloys of steel. Give their compositions and uses.
Name the constituents of Bronze.
For cryolite, explain its significance in the extraction of aluminium.
Name the following:
The chief ore of aluminium.
The following is an extract from 'Metals in the Service of Man, Alexander and Street/Pelican 1976':
| 'Alumina (aluminium oxide) has a very high melting point of over 2000°C so that it cannot readily be liquefied. However, conversion of alumina to aluminium and oxygen, by electrolysis, can occur when it is dissolved in some other substance.' |
- Which solution is used to react with bauxite as a first step in obtaining pure aluminium oxide?
- The aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the balanced chemical equation for this reaction.
- Name the element which serves both as the anode and the cathode in the extraction of aluminium.
- Write the balanced chemical equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
- Give the balanced chemical equation for the reaction which occurs at the anode when aluminium is purified by electrolysis.
Name the following :
The compound formed by the reaction between calcium oxide and silica.
Name the alloy used for the following purpose.
Surgical instruments
State the relevant reason for the following:
A layer of powered coke is used over the electrolytic mixture in Hall Heroult’s process.
State the relevant reason for the following:
Graphite anodes are continuously replaced during the electrolysis of alumina.
