Consider the following reduction process

${\mathrm{Zn}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Zn}\left(\mathrm{s}\right), {\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}E}}^{\mathrm{o}}=-0.76\mathrm{V}$

${\mathrm{Ca}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Ca}\left(\mathrm{s}\right),{\mathrm{E}}^{\mathrm{o}}=-2.87\mathrm{V}$

${\mathrm{Mg}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Mg}\left(\mathrm{s}\right),{\mathrm{E}}^{\mathrm{o}}=-2.36\mathrm{V}$

${\mathrm{Ni}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Ni}\left(\mathrm{s}\right),{\mathrm{E}}^{\mathrm{o}}=-0.25\mathrm{V}$. The reducing power of the metals increases in the order