Which of the following equations represents the cell potential?

Standard reduction potentials at $25^\circ C$ of $Li^{+}|Li$,$Ba^{2+}|Ba$,$Na^{+}|Na$,and $Mg^{2+}|Mg$ are $-3.05 \ V$,$-2.90 \ V$,$-2.71 \ V$,and $-2.37 \ V$ respectively. Which one of the following is the strongest oxidising agent?

For the reactions $Ag^{+} (aq) + e^{-} \rightarrow Ag_{(s)}$ and $Sn^{2+} (aq) + 2e^{-} \rightarrow Sn_{(s)}$,the standard electrode potentials at $25^{\circ}C$ are $0.80 \ V$ and $-0.14 \ V$ respectively. What is the standard $emf$ of the cell $Sn_{(s)} | Sn^{2+}_{(aq)} (1 \ M) || Ag^{+}_{(aq)} (1 \ M) | Ag_{(s)}$ in $volts$?

$Zn^{2+} + 2e^- \to Zn_{(s)}$; $E^o = -0.76 \ V$
$Fe^{3+} + e^- \to Fe^{2+}$; $E^o = +0.77 \ V$
$Cr^{3+} + 3e^- \to Cr_{(s)}$; $E^o = -0.74 \ V$
$H^{+} + e^- \to 1/2 H_2$; $E^o = 0.00 \ V$
Which of the following is the strongest reducing agent?

The standard electrode potential of $M^{+} / M$ in aqueous solution does not depend on

How would you determine the standard electrode potential of the system $Mg^{2+} | Mg$?