Which substance is used as an oxidising agent in a nickel-cadmium cell?

The standard free energy change $($ in $J)$ for the reaction $3 Fe^{2+}_{(aq)} + 2 Cr_{(s)} \rightleftharpoons 2 Cr^{3+}_{(aq)} + 3 Fe_{(s)}$ given $E_{Fe^{2+}/Fe}^{\circ} = -0.44 \, V$ and $E_{Cr^{3+}/Cr}^{\circ} = -0.74 \, V$ is $(F = 96500 \, C)$.

Depict the galvanic cell in which the reaction $Zn_{(s)} + 2Ag^{+}_{(aq)} \rightarrow Zn^{2+}_{(aq)} + 2Ag_{(s)}$ takes place,further show:
$(i)$ which of the electrode is negatively charged,
$(ii)$ the carriers of the current in the cell,and
$(iii)$ individual reaction at each electrode.

$Zn_{(s)} | Zn^{2+}_{(aq)} || Cu^{2+}_{(aq)} | Cu_{(s)}$ is

Given $\lambda^{\circ}_{Mg^{2+}} = 106 \ S \ cm^2 \ mole^{-1}$ and $\lambda^{\circ}_{SO_4^{2-}} = 160 \ S \ cm^2 \ mole^{-1}$. The value of $\lambda^{\circ}_{MgSO_4}$ (in $S \ cm^2 \ mole^{-1}$) is

Which substance is reduced in a dry cell?