Multiple Choice QuestionsThe chemical reaction that involves roasting process is
Fe2O3 + 3CO → 2Fe + 3CO2
2Al + Fe2O3 → 2Fe + Al2O3
2ZnS + 3O2 → 2ZnO + 3SO2
FeO + SiO2 → FeSiO3
Which one of the following oxides is reduced by water gas to obtain the metal during its extraction?
NiO
ZnO
WO3
Fe2O3
Which of the following is not added durig the extraction of silver by cyanide process?
NaCN
Air
Zn
Na2S2O3
D.
Na2S2O3
In the extraction of silver from cyanide process (also Mac-Arthur Forrest process), the siliver compound dissolve in NaCN solution forming a soluble complex salt, in presence of air, then silver is precipitated from this complex salt by the addition of Zn, because Zn being more reactive displaces the Ag.
Ag2S + 4NaCN 2Na[Ag(CN)2] + Na2S ↓
Na2S + 2O2 → Na2SO4
2Na[Ag(CN)2] + Zn → Na2[Zn(CN)4] + 2Ag ↓
What is the role of limestone during the extraction of iron from haematite ore?
Leaching agent
Oxidising agent
Reducing agent
Flux
After partial roasting the sulphide of copper is reduced by
reduction by carbon
electrolysis
self-reduction
cyanide process
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