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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
The process of leaching alumina, using sodium carbonate is called
- Bayer's process
- Decomposition
- Cyanide process
- Hall's process
Write chemical formulae of the following ores :
(a) Calamine
(b) Haematite
(c) Magnetite
(d) Corundum
Fe2O3 is reduced to spongy iron near the top of blast furance by
(A) H2
(B) CaO
(C) SiO2
(D) CO
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?
Name the method used for refining of copper metal.
Draw a neat, well labelled diagram of electrolytic cell for extraction of aluminium
The chemical formula of willemite is __
(a) ZnS
(b) ZnCO3
(c) ZnO
(d) Zn2SiO4
What is 'copper matte' ?
Describe the role of the cryolite in the extraction of aluminium from pure alumina.
How will you convert the following:
[Ag(CN)2]− to Ag
Metals which occur in their native state in nature:
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 electrolytic process for the extraction of aluminium the electrolyte is:-
Extraction of zinc from zinc blende is achieved by:-
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
Which of the following is not an ore of magnesiuim?
In the extraction of iron, the slag produce is
Match List I with List II.
| List - I | List - II | ||
| 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 option given below.
Calamine and Malachite, respectively, are the ores of ______.
The ore that contains both iron and copper is ______.
