Write down the reactions taking place in different Zones in the blast furnance during the extraction of Iron.
How can you separate alumina from silica in a baxuite ore associated with silica? Give equations, if any.
Name the processes from which chlorine is obtained as a bye-product. What will happen if an aqueous solution of NaCl is subjected to electrolysis?
Chlorine is obtained as a bye-product in Castner-Kallner process.
NaCl → Na+ + Cl–
Electrolysis of an aqueous solution of sodium chloride:
In aqueous solution, sodium chloride ionises
as:
NaCl(aq) → Na+(aq) + Cl– (aq)
When electricity is passed through the solution, the following reactions take place at the respective electrodes.
At Cathode: The reduction of H2O molecules take place in preference to the reduction of Na+ ions as:
2H2O + 2e– → 2OH– (aq) + H2(g)
At Anode : Cl– ions are preferentially liberated at the anode giving Cl2 gas.
The overall reaction representing electrolysis of aqueous solution of sodium chloride is
Outline the principles of refining of metals by the following methods:
(i) Zone refining.
(ii) Electrolytic refining.
(iii) Vapour phase refining.