Identify the direction of movement of electrons and ion flow in the electrolytic cell for the electrolysis of molten aluminium oxide.

Consider the overall reaction taking place in a voltaic cell.

${\mathrm{Ag}}_2\mathrm{O}\left(\mathrm{s}\right)+\mathrm{Zn}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\mathrm{Ag}\left(\mathrm{s}\right)+\mathrm{Zn}{\left(\mathrm{OH}\right)}_2\left(\mathrm{s}\right)$

What is the role of zinc in the cell?

Consider the following reactions of three unknown metals $\mathrm{X}$, $\mathrm{Y}$ and $\mathrm{Z}$.

$2{\mathrm{XNO}}_3\left(\mathrm{aq}\right)+\mathrm{Y}\left(\mathrm{s}\right)\to 2\mathrm{X}\left(\mathrm{s}\right)+\mathrm{Y}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)$

$\mathrm{Y}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)+\mathrm{Z}\left(\mathrm{s}\right)\to$no reaction

$2{\mathrm{XNO}}_3\left(\mathrm{aq}\right)+\mathrm{Z}\left(\mathrm{s}\right)\to 2\mathrm{X}\left(\mathrm{s}\right)+\mathrm{Z}{\left({\mathrm{NO}}_3\right)}_2\left(\mathrm{aq}\right)$

What is the order of increasing reactivity of the metals (least reactive first)?

What is the reducing agent in the reaction below?

$2{\mathrm{MnO}}_4^{-}\left(\mathrm{aq}\right)+{\mathrm{Br}}^{-}\left(\mathrm{aq}\right)+{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2{\mathrm{MnO}}_2\left(\mathrm{s}\right)+{\mathrm{BrO}}_3^{-}\left(\mathrm{aq}\right)+2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$.

Which changes could take place at the positive electrode (cathode) in a voltaic cell?

I. ${\mathrm{Zn}}^{2+}\left(\mathrm{aq}\right)$ to $\mathrm{Zn}\left(\mathrm{s}\right)$.

II. ${\mathrm{Cl}}_2\left(\mathrm{g}\right)$ to ${\mathrm{Cl}}^{-}\left(\mathrm{aq}\right)$.

III. $\mathrm{Mg}\left(\mathrm{s}\right)$ to ${\mathrm{Mg}}^{2+}\left(\mathrm{aq}\right)$.