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
