Gold is extracted by hydrometallurgical process, based on its property
of being electropositive
of being less reactive
to form complexes which are water soluble
to form salts which are water soluble
Which of the following taking place in the blast furnace is endothermic?
CaCO3 → CaO + CO2
2C + O2 → 2CO
C + O2 → CO2
Fe2O3 + 3CO → 2Fe + 3CO2
During the extraction of gold the following reactions take place
Au + CN- + H2O [X]
[X] + Zn → [Y] + Au
X and Y are respectively
[Au(CN)2]- and [Zn(CN)6]4-
[Au(CN)4]2- and [Zn(CN)4]2-
[Au(CN)4]3- and [Zn(CN)4]2-
[Au(CN)2]- and [Zn(CN4)]2-
Identifythe reaction that does not take place in a blast furnace
CaCO3 → CaO + CO2
CaO + SiO2 → CaSiO3
3Fe2O3 + 3C → 4Fe+ 3CO2
CO2 + C → 2CO
In the electrolytic refining of zinc
graphite is at the anode
the impure metal is at the cathode
the metal ion get reduced at the anode
acidified zinc sulphate is the electrolyte
The temperature of the slag zone in the metallurgy of iron using blast furnace is
1200 - 1500°C
1500 - 1600 °C
400 - 700°C
800 - 1000°C
Which one of the following statements is false?
During roasting, moisture is removed from the ore
The ore is freed from almost all non-metallic impurities
Calcination of ore is carried out in the absence of any blast of air
The concentrated zinc blende is subjected to calcination during its extraction by pyrometallurgy