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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 chemical formulae of the following ores :
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(b) Haematite
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(A) H2
(B) CaO
(C) SiO2
(D) CO
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(b)Hall process
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Write the names and chemical formulae of any ‘two’ minerals of aluminium.
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Passivation
The chemical formula of willemite is __
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(b) ZnCO3
(c) ZnO
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Metal which is found in free state is:
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Pyrolusite is ______.
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