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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
Silica is added to roasted copper ore during smelting process to remove _______.
(A) ferrous sulphide
(B) ferrous oxide
(C) cuprous sulphide
(D) cuprous oxide
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 CO in the extraction of Iron?
Which form of the iron is the purest form of commercial iron?
Differentiate between “minerals” and “ores”.
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:
Galvanization
Draw a neat, well labelled diagram of electrolytic cell for extraction of aluminium
Copper has the face centred cubic structure. The coordination number of each ion is:
Bauxite has the composition
Metals which occur in their native state in nature:
Which among the following statement is correct?
The sulphide ore of iron 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.
The main reactions occurring in blast furnace during extraction of iron from haematite are:
(i) \[\ce{Fe2O3 + 3CO -> 2Fe + 3CO2}\]
(ii) \[\ce{FeO + SiO2 -> FeSiO3}\]
(iii) \[\ce{Fe2O3 + 3C -> 2Fe + 3CO}\]
(iv) \[\ce{CaO + SiO2 -> CaSiO3}\]
Which of the following is not ore of aluminium?
Calamine and Malachite, respectively, are the ores of ______.
