Arrange the following metals in the order in which they displace each other from the solution of their salts: $Al, Cu, Fe, Mg$ and $Zn$.

The standard electrode potential for the two electrodes $A^{+}/A$ and $B^{+}/B$ are respectively $0.5 \ V$ and $0.75 \ V$. The $EMF$ of the given cell $A | A^{+}(a = 1) || B^{+}(a = 1) | B$ will be $.......... \ V$. (in $.25$)

Calculate the cell potential in volts for the cell reaction given below:
$Fe^{2+} + Zn \rightarrow Zn^{2+} + Fe$
Given:
$Zn \rightarrow Zn^{2+} + 2e^{-}, E^{0} = 0.76 \ V$
$Fe \rightarrow Fe^{2+} + 2e^{-}, E^{0} = 0.41 \ V$ (in $V$)

Reduction of species is dependent on its reduction potential value.

If standard reduction potentials $(E^0)$ of $(Al^{+3}(aq)|Al(s))$, $(Fe^{+2}(aq)|Fe(s))$, $(Cu^{+2}(aq)|Cu(s))$ and $(Ag^{+1}(aq)|Ag(s))$ are $-1.66 \text{ V}$, $-0.44 \text{ V}$, $+0.34 \text{ V}$ and $+0.79 \text{ V}$ respectively, which of the following reactions is non-spontaneous?

The $E^{\circ}$ of $Ce^{4+} / Ce^{3+} = 1.6 \ V$ and $Fe^{3+} / Fe^{2+} = 0.77 \ V$. The $E^{\circ}$ of the reaction where $Fe^{3+}$ oxidises $Ce^{3+}$ is: