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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 reactions involved in the zone of reduction in blast furnace during extraction of iron.
Silica is added to roasted copper ore during smelting process to remove _______.
(A) ferrous sulphide
(B) ferrous oxide
(C) cuprous sulphide
(D) cuprous oxide
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?
What is the role of CO in the extraction of Iron?
Indicate the principle behind the method used for the refining of zinc.
Which form of the iron is the purest form of commercial iron?
Name the method used for refining of copper metal.
Which of the ores mentioned can be concentrated by magnetic separation method?
Differentiate between “minerals” and “ores”.
Explain the following methods to protect metals from corrosion:
Passivation
What is the role of the following compound-
SiO2 in the extraction of copper from copper pyrites?
In the extraction of zinc from zinc blende:
(i) Give an equation to show how zinc oxide is converted to zinc.
(ii) How is impure zinc finally electro-refined?
How will you convert the following:
[Ag(CN)2]− to Ag
Bauxite has the composition
What are the differences between minerals and ores?
Metal which is found in free state is:
The sulphide ore of iron is ____________.
Which of the following options are correct?
(i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.
(ii) In extraction of silver, silver is extracted as cationic complex.
(iii) Nickel is purified by zone refining.
(iv) Zr and Ti are purified by van Arkel method.
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.
Which of the following reactions occur during calcination?
(i) \[\ce{CaCo3 -> CaO + CO2}\]
(ii) \[\ce{2FeS2 + 11/2 O2 -> Fe2O3 + 4SO2}\]
(iii) \[\ce{Al2O3. {x}H2O -> Al2O3 + {x}H2O}\]
(iv) \[\ce{ZnS + 3/2 O2 -> ZnO + SO2}\]
The important ore of iron is:-
In the thermite process, the reducing agent is:
In the electrolytic process for the extraction of aluminium the electrolyte is:-
Metal always found in Free State is
Which of the following is not an ore of magnesiuim?
Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?
Pyrolusite is ______.
