Advertisements
Advertisements
प्रश्न
The following is a sketch of an electrolytic cell used in the extraction of aluminium:
- What is the substance of which the electrodes A and B are made?
- At which electrode (A or B) is aluminium formed?
- What are the two aluminium compounds in the electrolyte C?
- Why is it necessary for electrode B to be continuously replaced?
उत्तर १
- Electrode A is made of carbon gas, and electrode B is made of carbon rods.
- At electrode A.
- Two compounds in the electrolyte C are Al2O3 and Na3AlF6.
- As at electrode B, oxygen is liberated during the process. The oxygen liberated oxidises the carbon anode, producing CO and CO2. Thus, electrode B is to be replaced continuously.
उत्तर २
- A is made of carbon and B is a thick graphite rod.
A → Cathode
B → Anode - Aluminium is generated at the cathode at A in a molten condition and can be extracted through a tapping hole.
- The two aluminium compounds in the electrolyte C are Na3AlF6 and Al2O3.
- At the anode, oxygen is released when it combines with carbon to create carbon monoxide. CO2 is created as the heated CO burns further. Consequently, the anode wears out and needs to be replaced periodically.
APPEARS IN
संबंधित प्रश्न
State the observations at the anode and at the cathode during the electrolysis of copper sulphate solution using copper electrodes.
Name a salt which is a weak electrolyte.
Define the term : Non-electrolyte
Write the equations for the reactions, which takes place at the electrodes during the electrolysis of lead bromide?
What kind of particles will be found in a liquid compound which is a non- electrolyte?
If HX is a weak acid, what particles will be present in its dilute solution apart from those of water?
Fill in the blank.
As we descend the electrochemical series containing cations, the tendency of the cations to get ________ at the cathode increases.
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 over 2000oC, so that I cannot readily be liquefied. However, conversion of alumina to aluminium and oxygen, by electrolysis, an occur when it is dissolved in some other substance.
(a) Which solution is used to react with bauxite as 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 extraction of aluminium by electrolysis.
(f) Give the equation for the reaction that occurs at the anode when aluminium is purified by electrolysis.
During the electrolysis of copper (II) sulphate solution using platinum as cathode and carbon as anode:
- What do you observe at the cathode and at the anode?
- What change is noticed in the electrolyte?
- Write the reactions at the cathode and at the anode.
Give appropriate scientific reasons for the following statement :
Carbon tetrachloride does not conduct electricity.
