A solution containing one mole per litre of each $Cu{(N{O_3})_2},\,\,AgN{O_3},\,\,H{g_2}{(N{O_3})_2}$ and $Mg{(N{O_3})_2},$ is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potentials) are $Ag/A{g^ + } = + 0.80,\,\,2Hg/Hg_2^{2 + } = + 0.79,\,\,Cu/C{u^{2 + }} = + 0.34,$$Mg/M{g^{2 + }} = - 2.37$with increasing voltage, the sequence of deposition of metals on the cathode will be
→$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,OH} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|} \\
{C{H_3} - C{H_2} - C - C{H_3}} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,} \\
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,Ph}
\end{array}$ can not be prepared by
→