Question

State your observation of the following case:

At the cathode when acidified aqueous copper sulphate solution is electrolyzed with copper electrodes.

Answer 1

Acidified aqueous copper sulphate solution is electrolysed with copper electrodes by electrolysis. The electrolysis of an aqueous solution of copper sulphate using copper electrodes (i.e. using active electrodes) results in the transfer of copper metal from the anode to the cathode during electrolysis. Copper sulphate is ionised in aqueous solution.

Chemical equation: \[\ce{CuSO4 -> Cu^{2+} + SO^{2-}4}\]

The positively charged copper ions migrate to the cathode, where each gains two electrons to become copper atoms deposited on the cathode.

\[\ce{Cu^{2+} + 2e- -> Cu}\]

Hence, the colour of copper sulphate changes from blue to colourless.