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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: \[\ce{Al^3+ + 3e^- -> Al_{(l)}}\]
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संबंधित प्रश्न
Name two metals which are highly resistant to corrosion.
Name one ore of copper (other than cuprite). Which compound of copper is present in this ore? Also, write its chemical formula.
Which metal is extracted from bauxite ore?
Describe the extraction of zinc metal from its sulphide ore (zinc blende). Write equations of the reactions involved.
An ore of manganese metal is:
(a) bauxite
(b) haematite
(c) cuprite
(d) pyrolusite
The major ore of aluminium is known as:
(a) cinnabar
(b) calamine
(c) bauxite
(d) pyrolusite
Calamine ore can be used to extract one of the following metals. This metal is:
(a) copper
(b) mercury
(c) aluminium
(d) zinc
Give the principles of the hydrolytic method.
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
Answer the following questions based on the extraction of aluminium from alumina by Hall - Heroult’s Process :
What is the function of cryolite used along with alumina as the electrolyte?
Name the following:
Two metals which are found in the free or native state.
Define the term:
Slag
Which method of refining is used to get 99.8% pure aluminium?
To protect iron from rusting, it is coated with a thin layer of zinc. Name the process.
Which one of the following is not true of metal :
Metals are malleable and ductile
Find the odd one out and give its explanation.
Explain the following reaction with the balanced equation.
Ferric oxide is reacted with aluminium.
Explain in brief electrolytic reduction of alumina with a neat labelled diagram.
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.
