Question

Write equations for the reactions taking place at the two electrodes (mentioning clearly the name of the electrode) during the electrolysis of acidified copper sulphate solution with copper electrodes.

Answer 1

Cathode: Copper

Anode: Platinum

Dissociation of aq. CuSO₄:

\[\ce{CuSO4 <=> Cu^{2+} + SO^{2-}_4}\]

\[\ce{H2O <=> H+ + OH-}\]

\[\ce{H2SO4 <=> 2H+ + SO^{2-}_4}\]

Reaction at cathode (pure thin sheet of Cu):

\[\ce{Cu^{2+} + 2e- -> Cu}\]    ...[Cu deposited on thin sheet]

Reaction at anode (impure block of active Cu):

\[\ce{Cu - 2e- -> Cu^{2+}}\]    ...[product nil - Cu²⁺ ions]