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प्रश्न
Write the chemical reactions involved in the extraction of gold by cyanide process. Also give the role of zinc in the extraction.
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उत्तर
\[\ce{4Au(s) + 8CN^{-} (aq) + 2H2O (aq) + O2(g) -> 4[Au(CN)2]^{-} (aq) + 4OH^{-} (aq)}\]
\[\ce{2[Au(CN)2]^{-} (aq) + Zn(s) -> 2Au(s) + [Zn(CN)4]^{2-} (aq)}\]
Zinc places the role of a reducing agent. It reduces \[\ce{Au+}\] to pure \[\ce{Au}\].
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संबंधित प्रश्न
Write the names and chemical formulae of any one ore of iron.
What is the chemical composition of malachite?
- CuO . CuC03
- Cu(OH)2 CuC03
- CuO.Cu(OH)2
- Cu2O . Cu(OH)2
Write the reactions involved in the zone of reduction in blast furnace during extraction of iron.
Draw neat and labelled diagram of Bessermer converter used in the extraction of copper.
What is the role of coke in the extraction of iron from its oxides?
Indicate the principle behind the method used for the refining of zinc.
Define Leaching.
Write the names and chemical formulae of any ‘two’ minerals of aluminium.
Explain the following methods to protect metals from corrosion:
Galvanization
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
Give the uses of zinc.
The most abundant metal on earth is:
Carbonate 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.
When a strip of metallic zinc is placed in an aqueous solution of copper nitrate the blue colour of the solution disappear due to formation of
In the electrolytic process for the extraction of aluminium the electrolyte is:-
Which of the following is not ore of aluminium?
Pyrolusite 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.
