$A$ standard hydrogen electrode has zero electrode potential because

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

Calculate the standard cell potential for a cell having the following reaction: $2 Al_{(s)} + 3 Ni^{2+} \rightarrow 2 Al^{3+} + 3 Ni_{(s)}$ given that $E_{Ni^{2+}/Ni}^{\circ} = -0.25 \ V$ and $E_{Al^{3+}/Al}^{\circ} = -1.66 \ V$. (in $V$)

The $E^{\circ}$ values of half-cells are given below. Which combination of two half-cells will result in a cell with the maximum potential?
$(i) \, A^{3-} \rightarrow A^{2-} + e^{-}; E^{\circ} = 1.5 \, V$
$(ii) \, B^{+} + e^{-} \rightarrow B; E^{\circ} = 0.5 \, V$
$(iii) \, C^{2+} + e^{-} \rightarrow C^{+}; E^{\circ} = 0.5 \, V$
$(iv) \, D \rightarrow D^{2+} + 2e^{-}; E^{\circ} = -1.15 \, V$

The standard electrode potential for the Daniell cell is $1.1 \ V$. What will be the value of standard Gibbs energy for the reaction?
$Zn_{(s)} + Cu_{(aq)}^{2+} \rightarrow Zn_{(aq)}^{2+} + Cu_{(s)}$
$(1 \ F = 96487 \ C \ mol^{-1})$

The reducing ability of the metals $K$,$Au$,$Zn$ and $Pb$ follows the order