Which from the following is the correct relationship between standard Gibbs energy change and standard cell potential?

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 $E^o$ values of $Mg^{2+}/Mg$ is $-2.37 \ V$,$Zn^{2+}/Zn$ is $-0.76 \ V$,and $Fe^{2+}/Fe$ is $-0.44 \ V$. Which of the following statements is correct?

Which of the following relations about $E^{\circ}_{cell}$ is false?

For $Mg^{2+} + 2e^{-} \rightarrow Mg_{(s)}$,$E^{0} = -2.37 \, V$ and for $Cu^{2+} + 2e^{-} \rightarrow Cu_{(s)}$,$E^{0} = +0.33 \, V$. The $emf$ of the cell $(E^{0}_{Cell})$ is .......... $V$.