A solution containing one mole per litre of each $\mathrm{Cu}{\left({\mathrm{NO}}_3\right)}_2,{\mathrm{AgNO}}_3,{\mathrm{Hg}}_2{\left({\mathrm{NO}}_3\right)}_2$ and $\mathrm{Mg}{\left({\mathrm{NO}}_3\right)}_2$ is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potentials) are $\mathrm{Ag}/{\mathrm{Ag}}^{+}=+0.80,2\mathrm{Hg}/{\mathrm{Hg}}_2^{2+}=+0.79,\mathrm{Cu}/{\mathrm{Cu}}^{2+}=+0.34,$ $\mathrm{Mg}/{\mathrm{Mg}}^{2+}=-2.37$V  with increasing voltage, the sequence of deposition of metals on the cathode will be