An aqueous solution of copper sulphate is electrolysed using platinum electodes in one case and copper electrodes in another case. Will the products of electrolysis be same or different? Give reason.

An aqueous solution of copper sulphate is electrolysed using platinum

1.	An aqueous solution of copper sulphate is electrolysed using platinum electodes in one case and copper electrodes in another case. Will the products of electrolysis be same or different? Give reason.
Answer» Solution :In case of platinum electrodes, the products are Cu on CATHODE and `O_(2)` gas on ANODE. This because out of `Cu^(2+) and OH^(+)` ions (produced from `H_(2)O`), `Cu^(2+)` ions have LOWER discharge potential. Out of `SO_(4)^(2-)` and `OH^(-)` ions, `OH^(-)` ions have lower discharge potential `(OH^(-)toOH+e^(-),CutoCu^(2+)+e^(-))` In case of copper electrodes, product at cathode is the same, viz, Cu but at anode, out of the THREE possible reactions, viz., `OH^(-)toOH+e,SO_(4)^(2-)toSO_(4)+2e^-,CutoCu^(2+)+2e^(-)` Cu is more easiliy oxidized than `OH^(-) and SO_(4)^(2-)` ions. HENCE, anode of Cu dissolves into the solution to form `Cu^(2+)` ions.