Electric current was passed through an aqueous solution of ${\mathrm{CuSO}}_4$ using two $\mathrm{Pt}$ electrodes. After some time, the blue colour of the solution disappeared along with evolution of ${\mathrm{O}}_2$ gas. Which of the following statement is correct regarding the resultant solution?

State one observation for the following:

Copper sulphate solution is electrolysed using copper electrodes.

For the electro-refining of copper, write the reaction that takes place at the anode.

Following reactions occur at the cathode during the electrolysis of aqueous silver chloride.

$$\begin{gathered} {\mathrm{Ag}}^{+}\left(\mathrm{aq}\right)+{\mathrm{e}}^{-}\to \mathrm{Ag}\left(\mathrm{s}\right); {\mathrm{E}}^{°}=+0.80 \mathrm{V} \\ {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{e}}^{-}\to \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right. {\mathrm{H}}_2\left(\mathrm{g}\right); {\mathrm{E}}^{°}=+0.00 \mathrm{V} \end{gathered}$$

On the basis of their standard reduction electrode potential$\left({\mathrm{E}}^{°}\right)$ values, which reaction is feasible at the cathode and why?

Draw the diagram of the apparatus used in electroplating and label the following part: 

The substance to be electroplated. 

Identify the substance underlined in the following:

The electrode that increases in mass during the electro-refining of silver.

Ions are the current carriers in electrolytes.

Sodium chloride in solid state is not an electrical conductor, but molten sodium chloride can conduct electricity. Give reason.

Ions are the current carriers in electrolytes.

What are the products obtained at anode and cathode during the electrolysis of molten sodium chloride?

The $\mathrm{pH}$ of the solution _________ during the electrolysis of dilute aqueous solution of ${\mathrm{CuSO}}_4.$