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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
The process of leaching alumina, using sodium carbonate is called
- Bayer's process
- Decomposition
- Cyanide process
- Hall's process
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
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.
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
The chemical formula of willemite is __
(a) ZnS
(b) ZnCO3
(c) ZnO
(d) Zn2SiO4
Describe the role of the cryolite in the extraction of aluminium from pure alumina.
What are the differences between minerals and ores?
The most abundant metal on earth is:
In the thermite process, the reducing agent is:
Which of the following is not ore of aluminium?
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?
Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?
The ore that contains both iron and copper is ______.
