Which of the following changes takes place at the positive electrode during the recharging of a lead accumulator?

Explain: Electrochemistry is a wide and interdisciplinary subject.

Give the symbolic representation of the galvanic cell obtained by using the following standard reduction potentials at $298 \ K$ and calculate its standard cell potential $(E^o_{cell})$.
$(i)$ $E^o_{Ag^{+}|Ag} = 0.80 \ V$
$(ii)$ $E^o_{Zn^{2+}|Zn} = -0.76 \ V$

$A$ cell reaction is spontaneous when

Write a note on the $Ni-Cd$ cell.

For the decomposition of $Al_2O_3$ at $500\,^{\circ}C$,the Gibbs energy change is given by $\frac{2}{3} Al_2O_3 \rightarrow \frac{4}{3} Al + O_2$,$\Delta G = 966 \, kJ \, mol^{-1}$. What is the potential difference (in $V$) required for the electrolytic reduction of $Al_2O_3$ at $500\,^{\circ}C$?