The standard electrode potentials $\left(E^{\circ }{\mathrm{M}}^{+}\mid \mathrm{M}\right)$ of four metals A, B, C and Dare -1.2 V, 0.6 V, 0.85 V and-0.76 V, respectively. The sequence of deposition of metals on applying potential is

The greater the reduction potential, the greater the tendency for the process ${\mathrm{M}}^{n+}+n{\mathrm{e}}^{-}\to \mathrm{M}$ to take place, and hence the more readily the discharge of ${\mathrm{M}}^{\mathrm{n}+}$ ions occur. Therefore, the sequence is $\mathrm{C}\left(0.85\mathrm{V}\right)>\mathrm{B}\left(0.6\mathrm{V}\right)>\mathrm{D}(-0.76\mathrm{V})>\mathrm{A}(-1.2\mathrm{V})$