Question

Which of the following can be observed if we allow current to pass through the given set up for some time?

• A. Copper gets deposited on the anode.
• B. Copper gets dissolved into the electrolyte from the cathode.
• C. Copper gets deposited on the cathode
• D. Copper residues settle down at the bottom.

Answer 1

The correct option is C Copper gets deposited on the cathode

In the given experimental set up, the copper plate connected to the positive terminal of the battery acts as the anode and the one connected to the negative terminal acts as the cathode. The copper sulphate solution $\left({\text{CuSO}}_4\right)$ acts as an electrolyte.

When electric current is passed through this copper sulphate solution it dissociates into ${\text{Cu}}^{2+}$ and ${\text{SO}}_4^{2-}$ ions.

These ions move from the electrolyte towards the cathode and anode respectively. The reaction that takes place at anode is:

$\text{Cu (s)}\to {\text{Cu}}^{2+}\text{(aq)}+2{\text{e}}^{-}$

The reaction that takes place at cathode is:

${\text{Cu}}^{2+}\text{(aq)}+2{\text{e}}^{-}\to \text{Cu (s)}$

Thus, copper gets deposited on the cathode.