$Mg^{2+}$ displaces hydrogen from acids but copper does not. $A$ galvanic cell prepared by combining $Cu/Cu^{2+}$ and $Mg/Mg^{2+}$ has an $EMF$ of $2.71 \ V$ at $298 \ K$. If the potential of copper electrode is $0.34 \ V$,what is the reduction potential of $Mg$ electrode?

Can $E_{cell}^o$ or $\Delta_r G^o$ for a cell reaction ever be equal to zero?

Given are $E^{\circ}$ values for some half reactions:
$I_2 + 2e^{-} \to 2I^{-}$ ; $E^{\circ} = 0.54 \, V$
$MnO_4^{-} + 8H^{+} + 5e^{-} \to Mn^{2+} + 4H_2O$ ; $E^{\circ} = 1.52 \, V$
$Fe^{3+} + e^{-} \to Fe^{2+}$ ; $E^{\circ} = 0.77 \, V$
$Sn^{4+} + 2e^{-} \to Sn^{2+}$ ; $E^{\circ} = 0.1 \, V$
The strongest reducant and oxidant respectively are:

The standard $E^{\circ}_{red}$ values of $A, B$ and $C$ are $+0.68 \ V, -2.54 \ V$ and $-0.50 \ V$ respectively. The order of their reducing power is:

$A$ gas $X$ at $1 \, atm$ is bubbled through a solution containing a mixture of $1 \, M \, Y^{-}$ and $1 \, M \, Z^{-}$ at $25 \, ^oC$. If the reduction potential of $Z > Y > X$,then

On the basis of the following electrode potentials,which one is the strongest reducing agent?
$E^0_{Cr_2O_7^{2-}/Cr^{3+}} = 1.33 \text{ V}$,$E^0_{MnO_4^-/Mn^{2+}} = 1.51 \text{ V}$,$E^0_{Br_2/Br^{-}} = 1.09 \text{ V}$,$E^0_{Zn^{2+}/Zn} = -0.76 \text{ V}$