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प्रश्न
Explain why In the electrolysis of alumina using the Hall Heroult's Process the electrolyte is covered with powdered coke
उत्तर
In the electrolysis of alumina using the Hall–Héroult process, the electrolyte is covered with powdered coke as it
- reduces heat loss by radiation
- prevents the burning of the anode
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संबंधित प्रश्न
Give reason for the following:
Extraction of aluminium was very difficult in the beginning.
What is the role of cryolite (NaAlF6) in the electrolytic reduction of alumina in the Hall's process?
For the substance listed below, explain its role in the extraction of aluminium: Graphite
Aluminium is extracted from its chief ore bauxite. The ore is first purified and then the metal is extracted from it by electrolytic reduction.
Mention one reason for the use of aluminium in thermite welding. Which particular property of cast iron makes it unsuitable for the construction of bridges?
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.
The sketch below illustrates the refin ing of aluminium by Hoope's process
(a) Which of A and B is th e cathode and which one is the anode?
(b) What is the electroly te in the tank?
( c) What material is used for th e cathode?
Describe the role played in the extraction of aluminum:
Sodium hydroxide
Explain with reason:
A neutral gas other than oxygen is formed at the anode during the electrolysis of fused alumina.
Answer the following question:
Write the chemical formula of one main ore of iron and aluminium.
Given below in column A is a schematic diagram of the electrolytic reduction of alumina. Identify the parts labelled as A, B and C with the correct options from the Column B.
| column A | column B | |
 |
1. | Platinum |
| 2. | Anode | |
| 3. | Cathode | |
| 4. | Electrolyte mixture | |
| 5. | Bauxite |
