$FeO_4^{2-}$ $\xrightarrow{2.2 \ V} Fe^{3+}$ $\xrightarrow{0.70 \ V} Fe^{2+}$ $\xrightarrow{-0.45 \ V} Fe^0$
$E_{FeO_4^{2-} / Fe^{2+}}^{\theta}$ is $x \times 10^{-3} \ V$. The value of $x$ is $.........$.

$FeO_4^{2-}$ $\xrightarrow{2.0 \ V} Fe^{3+}$ $\xrightarrow{0.8 \ V} Fe^{2+}$ $\xrightarrow{-0.44 \ V} Fe^0$
In the above diagram,the standard electrode potentials are given in volts. The value of $E_{FeO_4^{2-}/Fe^{2+}}^{\Theta}$ is: (in $V$)

The $E^{0}_{Red}$ values of $A, B, C,$ and $D$ are $0.8 \, V, 0.79 \, V, 0.34 \, V,$ and $-2.37 \, V$ respectively. Which element can displace the other three from their salt solutions?

The standard reduction potential $E^{\circ}$ for half reactions are

$Zn \rightarrow Zn^{2+} + 2e^-$	$E^{\circ} = +0.76 \ V$
$Fe \rightarrow Fe^{2+} + 2e^-$	$E^{\circ} = +0.41 \ V$

The $EMF$ of the cell reaction $Fe^{2+} + Zn \rightarrow Zn^{2+} + Fe$ is

Two half-cell reactions are given below:
$Co^{3+} + e^- \rightarrow Co^{2+}, E^{\circ}_{Co^{3+}/Co^{2+}} = 1.81 \, V$
$Al^{3+} + 3e^- \rightarrow Al(s), E^{\circ}_{Al^{3+}/Al} = -1.66 \, V$
The standard $EMF$ of a cell with a feasible redox reaction will be:

For the reaction taking place in the cell:
$Pt_{(s)} | H_{2(g)} | H^{+}_{(aq)} || Ag^{+}_{(aq)} | Ag_{(s)}$
$E_{Cell}^0 = +0.5332 \ V$.
The value of $\Delta_f G^0$ in $kJ \ mol^{-1}$ (nearest integer) is: