Name the processes from which chlorine is obtained as a by-product. What will happen if an aqueous solution of NaCl is subjected to electrolysis?

Name the processes from which chlorine is obtained as a by-product. Wh

1.	Name the processes from which chlorine is obtained as a by-product. What will happen if an aqueous solution of NaCl is subjected to electrolysis?
Answer» Solution :Sodium METAL is prepared by Down.s process. It involves the electrolysis of a fused mixture of NaCl and `CaCl_(2)` at 873 K. During electrolysis sodium is discharged at the cathode while `Cl_(2)` is obatained at the anode as a by-product. `NaCl(l) overset(" Electrolysis ")(to) Na^(+) (" melt ")+Cl^(-) (" melt ")` At cathode : `Na^(+) (" melt ")+e^(-) to Na(s)` At anode : `Cl^(-) (" melt ")to Cl(G) +e^(-)` `2Cl(g) to Cl_(2)(g)`. If, however, an aqueous solution of NaCl is electrolysed, `H_(2)` is evolved at the cathode while `Cl_(2)` is obtained at the anode. The reason being that the `E^(0)" of "Na^(+)"/"Na` redox couple is much lower `(E^(0)= -2.71 V)` than that of `H_(2)O (E_(H_(2)O"/"H_(2))^(0)= -0.83V)` and HENCE water is reduced of `H_(2)` in preference to `Na^(+)` IONS. Lower the reduction potential `(E^(0))`, greater is the EASE of deposition at cathode. NaOH is obtained in the solution. `NaCl(aq) overset(" Electrolysis ")(to) Na^(+) (aq)+ Cl^(-)(aq)` At anode : `Cl^(-)(aq) to Cl (g) +e^(-)` `Cl(g) to Cl_(2)(g)` At cathode : `2H_(2)O(l)+2e^(-) to H_(2)(g)+2OH^(-)(aq)`.