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प्रश्न
Explain the following methods to protect metals from corrosion:
Galvanization
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.
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 cryolite in the extraction of aluminium?
Describe the roles of the following: SiO2 in the extraction of copper from copper matte
Name the method used for refining of copper metal.
Differentiate between “minerals” and “ores”.
Define Leaching.
Write the names and chemical formulae of any ‘two’ minerals of aluminium.
Explain the following methods to protect metals from corrosion:
Passivation
Draw a neat, well labelled diagram of electrolytic cell for extraction of aluminium
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?
What happens when a nickel rod is dipped into a copper sulphate solution? Justify your answer.
`[E_((Ni^(+2))/(Ni))^0 = -0.25"v" and E _(("Cu"^(+2))/("Cu"))^0 = +0.34"v"]`
Bauxite has the composition
Metals which occur in their native state in nature:
The most abundant metal on earth is:
Carbonate ore of iron is ____________.
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) \[\ce{ZnS + 3/2 O2 -> ZnO + SO2}\]
Identify a mineral for the major source of boron from the following list?
Which of the following is not ore of aluminium?
Metal always found in Free State is
Native silver metal forms a water solution complex with dilute solution of Na CN in the presence of
Match List - I with List - II.
| List - I | List - II | ||
| (One) | (Composition) | ||
| (A) | Siderite | (I) | FeCO3 |
| (B) | Malachite | (II) | CuCO3 · Cu(OH)2 |
| (C) | Sphalerite | (III) | ZnS |
| (D) | Calamine | (IV) | ZnCO3 |
Choose the correct answer from the options given below:
The ore that contains both iron and copper is ______.
