$Cu^{+} + e^- \to Cu$ ; $E^o = X_1 \ V$
$Cu^{2+} + 2e^- \to Cu$ ; $E^o = X_2 \ V$
Then for $Cu^{2+} + e^- \to Cu^{+}$ ; $E^o$ will be ?

What is $emf$?

The $E^o$ values of half-cells are given below. Which combination of two half-cells will form a cell with the maximum potential?
$(i)$ $A + e^- \rightarrow A^- ; E^o = -0.24 \ V$
$(ii)$ $B^- + e^- \rightarrow B^{2-} ; E^o = +1.25 \ V$
$(iii)$ $C^- + 2e^- \rightarrow C^{3-} ; E^o = -1.25 \ V$
$(iv)$ $D + 2e^- \rightarrow D^{2-} ; E^o = +0.68 \ V$

The oxidation potentials of the following half-cell reactions are given:
$Zn \to Zn^{2+} + 2e^-; E^o = 0.76 \, V$
$Fe \to Fe^{2+} + 2e^-; E^o = 0.44 \, V$
What will be the $EMF$ of the cell whose cell reaction is:
$Fe^{2+}_{(aq)} + Zn \to Zn^{2+}_{(aq)} + Fe$

What is cell potential and $emf$? Explain with suitable examples.

The standard electrode potentials are: $K^{+}/K = -2.93 \ V$,$Ag^{+}/Ag = 0.80 \ V$,$Hg^{2+}/Hg = 0.79 \ V$,$Mg^{2+}/Mg = -2.37 \ V$,$Cr^{3+}/Cr = -0.74 \ V$. Arrange these metals in the increasing order of their reducing power.