Which one of the following processes is non-spontaneous?

In a $Cu-Zn$ cell,.....

Using the standard electrode potentials given in Table $3.1$ of the $NCERT$ textbook,predict if the reaction between the following is feasible:
$(i)$ $Fe^{3+}_{(aq)}$ and $I^{-}_{(aq)}$
$(ii)$ $Ag^{+}_{(aq)}$ and $Cu_{(s)}$
$(iii)$ $Fe^{3+}_{(aq)}$ and $Br^{-}_{(aq)}$
$(iv)$ $Ag_{(s)}$ and $Fe^{3+}_{(aq)}$
$(v)$ $Br_{2(aq)}$ and $Fe^{2+}_{(aq)}$

In a dry cell,which element acts as the negative electrode?

The Gibbs energy for the decomposition of $Al_2O_3$ at $500\,^oC$ is as follows:
$\frac{2}{3}Al_2O_3 \to \frac{4}{3}Al + O_2, \Delta_rG = +940\,kJ\,mol^{-1}$
The potential difference needed for the electrolytic reduction of aluminium oxide is ............... $V$.

Standard hydrogen electrode $(SHE)$ is a