${\mathrm{FeO}}_4^{2-}\stackrel{+2.0\mathrm{V}}{\to }{\mathrm{Fe}}^{3+}\stackrel{0.8\mathrm{V}}{\to }{\mathrm{Fe}}^{2+}\stackrel{-0.5\mathrm{V}}{\to }{\mathrm{Fe}}^0$

In the above diagram, the standard electrodepotentials are given in volts (over the arrow). The value of ${\mathrm{E}}_{{\mathrm{FeO}}_4^{2-}/{\mathrm{Fe}}^{2+}}^{\mathrm{\Theta }}$ is