Question

What will happen during the electrolysis of aqueous solution of cuso4 by using platinum electrodes?

Answer 1

CuSO4 ⇋ Cu2+ + SO24-

H2O ⇋ H+ + OH-

At cathode,

Cu2+ + 2e- __> Cu2; Eocell = 0.34 V

H+ + e- __> H2; Eocell = 0.00 V

(i) reaction will take place due to higher reduction potential.

At anode,

2SO24- - 2e- __> SO28-; Eocell = 1.96 V

2H2O __> O2 + 4H+ 4e-; Eocell = 1.23 V

The reaction with lower value of Eo will be preferred at anode, hence O2 is released at anode.