Question

explain why the blue colour of copper chloride fades away gradually during electrolysis?

Answer 1

See this question depends upon the type of electrodes being used.
In case of active electrodes like copper plates, simultaneously copper ions are produced on anode which will maintain blue color of cuso4 soln.
In case of inert electrodes like graphite plates no copper ions are produced but oxygen gas is produced (aqueous cuso4) so blue color fades away