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प्रश्न
Observe the figure and answer the following.
- Write the name of the method.
- What is used as anode and cathode in this method?
- Write the molecular formula and use of cryolite.
- Write anode reaction.
- Write cathode reaction.
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उत्तर
- The method shown is an electrolytic reduction of alumina.
- A set of graphite rods dipped in the molten electrolyte acts as the anode. and the graphite lining acts as a cathode.
- Molecular formula of cryolite: Na3AlF6
Use of cryolite: Addition of cryolite reduces the melting point of alumina to about 1000 °C. - Anode reaction: \[\ce{2O^2+ -> O2 + 4e^-}\]
- Cathode reaction: \[\ce{Al^3+ + 3e^- -> Al_{(l)}}\]
APPEARS IN
संबंधित प्रश्न
Name a reducing agent that may be used to obtain manganese from manganese dioxide.
Why does aluminium not corrode right through?
Name two metals which occur in nature in free state as well as in combined state.
Name the metal which is extracted from haematite ore.
How is aluminium metal extracted? Explain with the help of an equation.
Name the electrode at which aluminium metal is produced.
Zinc blende ore can be converted into zinc oxide by the process of:
(a) roasting
(b) hydrogenation
(c) chlorination
(d) calcination
Identify the process given in following passage and draw neat labelled diagram showing the process.
Electrolysis of molten mixture of alumina (melting point > 20000C) is done in a steel tank. The tank has a graphite lining on the inner side. This lining does the work of a cathode. A set of graphite rods dipped in the molten electrolyte works as anode. Cryolite (Na3AlF6) and fluorspar (CaF2) are added in the mixture to lower its melting point upto 10000C.
Give the chemical formula of :
Cryolite
Name the following:
Name two metals always find in combined state.
Define the term:
Slag
How are metals refined by the electrolytic methods?
How many valence electrons are present in non- metals?
To protect iron from rusting, it is coated with a thin layer of zinc. Name the process.
What is the difference between calcination and roasting?
How is the method of extraction of metals high up in the reactivity series different from that for metals in the middle? Why can the same process not be applied for them? Name the process used for the extraction of these metals.
If Cu, Fe, Zn, Al elements are arranged in increasing order of their reactivity then the correct order would be which of the following?
Aluminium oxide is _______ oxide.
In the electrolytic method, a layer of highly active metal is applied to a less active metal.
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
