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प्रश्न
Observe the following diagram and write answers.
- Name the method.
- Write anode reaction and cathode reaction.
- Why fluorspar and cryolite are added in the mixture?
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उत्तर
- This method is electrolytic reduction of alumina.
- Anode reaction:
\[\ce{2O^{2-} -> O2 + 4e^-}\] (Oxidation)
Cathode reaction:
\[\ce{Al^{3+} + 3e^- -> Al_{(l)}}\] (Reduction) - Alumina has a very high melting point (>2000 °C). The purpose of mixing ‘cryolite’ and ‘fluorspar’ with ‘alumina’ in the electrolytic reduction of alumina is to carry out the process at a much lower temperature. Addition of cryolite and fluorspar reduces the melting point of alumina to about 1000 °C.
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संबंधित प्रश्न
Metallic oxides of zinc, magnesium and copper were heated with the following metals.
| Metal | Zinc | Magnesium | Copper |
| Zinc oxide | – | – | – |
| Magnesium oxide | – | – | – |
| Copper oxide | – | – | – |
In which cases will you find displacement reactions taking place?
In the extraction of aluminium: Write the function and formula of cryolite in the extraction of aluminium.
Name a reducing agent that may be used to obtain manganese from manganese dioxide.
Explain giving one example, how highly reactive metals (which are high up in the reactivity series) are extracted.
Explain givem equation, what happens when a mixture of Cu2O and Cu2S is heated?
Name the metal which is extracted from haematite ore.
Name two ores of zinc. Write the names of the chemical compounds present in them and give their chemical formulae.
The metal which can be extracted from the bauxite ore is:
(a) Na
(b) Mn
(c) Al
(d) Hg
Calamine ore can be used to extract one of the following metals. This metal is:
(a) copper
(b) mercury
(c) aluminium
(d) zinc
Aluminum is used in thermite welding:
what is thermit?
How an ore is concentrated by froth floatation process?
Complete the incomplete statement with missing word:
Metals form positive ions while non- metals ______.
How many valence electrons are present in metals ?
Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as ______.
Name the process used for the enrichment of sulphide ore.
In electrolytic reduction of alumina _______ is used as a cathode.
Identify who I am!
Ore of Aluminum- ______
Explain the reactions of nonmetals with water with the help of examples.
Explain the following reaction with the balanced equation.
Zinc carbonate is heated strongly in limited supply of air
Explain in brief types of extraction of less reactive metals according to their reactivity.
