Which of the following is the weakest reducing agent?

Given
$E^o_{\frac{1}{2}Cl_2/Cl^-} = 1.36 \ V$,$E^o_{Cr^{3+}/Cr} = -0.74 \ V$
$E^o_{Cr_2O_7^{2-}/Cr^{3+}} = 1.33 \ V$,$E^o_{MnO_4^-/Mn^{2+}} = 1.51 \ V$
The correct order of reducing power of the species $(Cr, Cr^{3+}, Mn^{2+}, Cl^-)$ will be:

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 $volts$?

If $E^o_{A^{+2}/A} = -0.30 \ V$ and $E^o_{A^{+3}/A^{+2}} = 0.40 \ V$,the standard $EMF$ of the reaction: $A + 2A^{+3} \to 3A^{+2}$ will be ............ $V$.

Which metal among the following has the strongest tendency to undergo oxidation?

For the half-reactions $Zn \rightarrow Zn^{2+} + 2e^{-}$ and $Fe \rightarrow Fe^{2+} + 2e^{-}$,the standard oxidation potentials are given as $E^{0}_{Oxi} = +0.76 \ V$ and $E^{0}_{Oxi} = +0.41 \ V$ respectively. Calculate the cell potential for the reaction $Fe^{2+} + Zn \rightarrow Zn^{2+} + Fe$ in $V$.