Two pieces of blue litmmus paper are placed in cathode and anode compartments of an electrolytic cell used for electrolysis of `Na_(2)SO_(4)` solution. Will the colour of the litmus paper change during electrolysis?

Explanation

Anode reaction : `2H_(2)O(l)rarr O_(2)(g)+4H^(+)+4e`
Cathode reaction : `4H_(2)O(l)+4 rarr 2H_(2)(g)+4OH^(-)(aq)`
There will be no change in colour of the blue litmus paper in the cathode compartment due to the formation of `OH^(-)(aq)` ions. However, the colour changes to red in the anode compartment due to the formation of `H^(+)` ions.