The following questions are related to the extraction of aluminum by electrolysis.
Name the other aluminum-containing compound added to alumina and state its significance.
Give the equation for the reaction that takes place at the cathode.
Explain, why is it necessary to renew the anode periodically?

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Solution

I. The other aluminum-containing compound added to alumina is cryolite. For alumina, it acts as a solvent. Then it decreased the fusion temperature from 2050 degrees to 950 degrees. It enhances the conductivity.
Hence, The answer is Cryolite
II. The equation for the reaction that takes place at the cathode is, ${Al}^{3 +} + 3 e \to Al$
Hence, The answer is ${Al}^{3 +} + 3 e \to Al$
III. At the anode, oxygen gas is formed during the electrolysis process. The oxidizing of the graphite anode produces carbon dioxide. So that it can be sure to replace the anode periodically.

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Similar questions

Q. The following questions relate to the extraction of aluminium by electrolysis.
(a) Give the equation for the reaction which takes place at the cathode.
(b) Explain, why it is necessary to renew the anode periodically.

Q. 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.
(a) Which solution is used to react with bauxite as a first step in obtaining pure aluminium oxide?
(b) The aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the equation for this reaction.
(c) Name the element which serves both as the anode and the cathode in the extraction of aluminium.
(d) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium.
(e) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
(f) Give the equation for the reaction that occurs at the anode when aluminium is purified by electrolysis.

Q. 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'.
(a) Which solution is used to react with bauxite as a first step in obtaining pure aluminium oxide?
(b) The aluminium oxide for the electrolytic extraction of aluminium is obtained by heating aluminium hydroxide. Write the balanced chemical equation for this reaction.
(c) Name the element which serves both as anode and the cathode in the extraction of aluminium.
(d) Write the balanced chemical equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
(e) Give the balanced chemical equation for the reaction which occurs at the anode when aluminium is purified by electrolysis.

The following questions are related to the extraction of aluminum by electrolysis. (i) Name the other aluminum-containing compound added to alumina and state its significance. (ii) Give the equation for the reaction that takes place at the cathode. (iii) Explain, why is it necessary to renew the anode periodically?

The following questions relate to the extraction of aluminum by electrolysis:

Name the other aluminum-containing compound added to alumina and state its significance.

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