Short Answer TypeOut of C and CO, which is a better reducing agent at the lower temperature range in the blast furnace to extract iron from the oxide ore?
Describe the principle involved in each of the following processes.
(i) Mond process for refining of Nickel.
(ii) Column chromatography for purification of rare elements.
Explain how the phenomenon of adsorption finds application in each of the following processes:
(i) Production of vacuum
(ii) Heterogeneous catalysis
(iii)Froth Floatation process
Describe the principle behind each of the following processes:
(i)Vapour phase refining of a metal.
(ii)Electrolytic refining of a metal.
(iii)Recovery of silver after silver ore was leached with NaCN.
(i) What is the principle behind the zone refining of metals?
(ii) What is the role of silica in the extraction of copper?
(iii) How is 'cast iron' different from 'pig iron'?
(i) The technique of zone refining is based on the principle that the impurities are more soluble in the molten state of metal than in the solid state. Silicon , boron gallium , indium etc. can purify by this process.
(ii) Ores of copper contain iron oxide as an impurity. Silica reacts with iron oxide and forms iron silicate, which is removed as slag.
FeO + SiO2 -------> FeSiO3
Iron oxide silica iron silicate (slag)
(iii) The iron obtained from the blast furnace is known as pig iron. It contains around 4% carbon and many impurities, such as S, P, Si, Mn, in smaller amounts.
Cast iron is obtained by melting pig iron and coke using a hot air blast. It contains a lower amount of carbon (about 3%) than pig iron. Unlike pig iron, cast iron is extremely hard and brittle.
Outline the principles of refining of metals by the following methods:
(i) Zone refining
(ii) Vapour phase refining
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