Which is the increasing order of reducing power of the following metals on the basis of standard electrode potential? $Ag^{+}/Ag = 0.80 \ V$,$Mg^{2+}/Mg = -2.37 \ V$,$Hg^{2+}/Hg = 0.79 \ V$,$Cr^{3+}/Cr = -0.74 \ V$

Given electrode potentials:
$Fe^{3+} + e^- \to Fe^{2+}$; $E^o = 0.771 \, V$
$I_2 + 2e^- \to 2I^-$; $E^o = 0.536 \, V$
$E^o_{\text{cell}}$ for the cell reaction
$2Fe^{3+} + 2I^- \to 2Fe^{2+} + I_2$ is:

The standard electrode potentials of two half-cells are given as: $Ni^{2+}_{(aq)} + 2e^{-} \rightarrow Ni_{(s)}$; $E^o = -0.25 \ V$ and $Zn^{2+}_{(aq)} + 2e^{-} \rightarrow Zn_{(s)}$; $E^o = -0.76 \ V$. What is the standard $emf$ of the cell formed by connecting these two half-cells in $volt$?

If the reduction potential is more,then

The standard reduction potentials of $Zn^{2+}|Zn$,$Cu^{2+}|Cu$ and $Ag^{+}|Ag$ are respectively $-0.76 \ V$,$0.34 \ V$ and $0.80 \ V$. The following cells were constructed:
$(1)$ $Zn|Zn^{2+}||Cu^{2+}|Cu$
$(2)$ $Zn|Zn^{2+}||Ag^{+}|Ag$
$(3)$ $Cu|Cu^{2+}||Ag^{+}|Ag$
What is the correct order of $E_{\text{cell}}^{\circ}$ of these cells?

When oxidation and reduction take place in a cell,its electromotive force $(EMF)$ will be