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प्रश्न
Explain the following methods to protect metals from corrosion:
Galvanization
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उत्तर
Galvanization:
1) The rusting of iron can be prevented by coating the metal surface with another metal such as zinc, that is oxidized in preference to iron. This process is called galvanization.
2) If the zinc layer is scratched, even then it protects iron from corrosion as long as Fe and Zn are in contact. If Fe is oxidized to Fe2+, then Zn immediately reduces Fe2+ back to Fe.
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संबंधित प्रश्न
Write the names and chemical formulae of any one ore of zinc.
Write the names and chemical formulae of any one ore of iron.
The process of leaching alumina, using sodium carbonate is called
- Bayer's process
- Decomposition
- Cyanide process
- Hall's process
Silica is added to roasted copper ore during smelting process to remove _______.
(A) ferrous sulphide
(B) ferrous oxide
(C) cuprous sulphide
(D) cuprous oxide
Write chemical formulae of the following ores :
(a) Calamine
(b) Haematite
(c) Magnetite
(d) Corundum
Out of C and CO, which is a better reducing agent at the lower temperature range in the blast furnace to extract iron from the oxide ore?
Purification of aluminium by electrolytic refining is carried out by
(a)Hoope process
(b)Hall process
(c)Baeyer process
(d)Serperck process
What is the role of cryolite in the extraction of aluminium?
What is the role of CO in the extraction of Iron?
In the extraction of Al, impure Al2O3 is dissolved in conc. NaOH to form sodium aluminate and leaving impurities behind. What is the name of this process?
Describe the roles of the following: SiO2 in the extraction of copper from copper matte
Name the method used for refining of copper metal.
Which among the following minerals does NOT contain aluminium?
(a) Cryolite
(b) Siderite
(c) China clay
(d) Corundum
Explain the following methods to protect metals from corrosion:
Passivation
Why does copper obtained in the extraction from copper pyrites have a blistered appearance?
What is the role of the following compound-
SiO2 in the extraction of copper from copper pyrites?
Bauxite has the composition
Metal which is found in free state is:
Carbonate ore of iron is ____________.
In the extraction of aluminium by Hall-Heroult process, purified \[\ce{Al2O3}\] is mixed with \[\ce{CaF2}\] to:
(i) lower the melting point of \[\ce{Al2O3}\].
(ii) increase the conductivity of molten mixture.
(iii) reduce \[\ce{Al^{3+}}\] into \[\ce{Al(s)}\].
(iv) acts as catalyst.
Write the chemical reactions involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.
The important ore of iron is:-
In the thermite process, the reducing agent is:
In the extraction of iron, the slag produce is
Pyrolusite is ______.
Calamine and Malachite, respectively, are the ores of ______.
