# What would occur in the electrolytic reduction of Cu^(2+)?

## What would occur in the electrolytic reduction of $C {u}^{2 +}$? $\text{a. the cathode would decrease in mass, and the anode would increase in mass.}$ $\text{b. the colour of the solution would dissipate.}$ $\text{c. the blue colour of the solution would slowly dissipate, and the cathode would acquire a salmon pink coating.}$ $\text{d. copper salts do not undergo electrolytic reaction, and there would be no macroscopic change.}$

Jun 1, 2016

$\text{Option C}$

#### Explanation:

The $C u {\left(O {H}_{2}\right)}_{6}^{2 +}$ species, which we could also represent as $C {u}^{2 +} \left(a q\right)$, gives a beautiful blue colour in aqueous solution.

In this experiment, $C {u}^{2 +} \left(a q\right)$ is reduced at the cathode to give it a copper coating according to the reaction:

$C {u}^{2 +} \left(a q\right) + 2 {e}^{-} \rightarrow C u \left(s\right) \downarrow$.

As the experiment progresses, the concentration of the solution decreases, and accordingly the colour of the solution fades. Meanwhile the cathode acquires a thin plating of copper metal.