A solution containing one mole per litre of each $Cu(NO_3)_2$, $AgNO_3,Hg_2(NO_3)_2$ and $Mg(NO_3)_2$ is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts (reduction potential) are
$\hspace15mm Ag^+/ Ag =+0.80, Hg^{2+}_2/2Hg=+0.79 $
$\hspace15mm Cu^+/ Cu =+0.34, Mg^{2+}/Mg=-2.37 $
With increasing voltage, the sequence of deposition of metals or the cathode will be