Question

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

Answer 1

Electrolysis is a process of dissociation of a compound into its constituent elements on a passing current.

Electrolysis of copper sulphate solution with copper electrodes gives copper ion and sulphate ion in the solution.

$$\begin{gathered} {\mathrm{CuSO}}_4\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+{\mathrm{SO}}_4^{2-}\left(\mathrm{aq}\right) \\ \mathrm{copper}\mathrm{copper}\mathrm{sulphate} \\ \mathrm{sulphate}\mathrm{ion}\mathrm{ion} \end{gathered}$$

At anode: oxidation of copper metal is occurred by losing the electron to give copper ions.

$$\begin{gathered} \mathrm{Cu}\left(\mathrm{s}\right)\to {\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-} \\ \mathrm{copper}\mathrm{copper} \\ \mathrm{atom}\mathrm{ion} \end{gathered}$$

At cathode: Reduction is occurred by gaining of electrons by copper ions to form copper atom.

${\mathrm{Cu}}^{2+}\left(\mathrm{aq}\right)+2{\mathrm{e}}^{-}\to \mathrm{Cu}\left(\mathrm{s}\right)$