Which of the following statements is true for a standard electrochemical cell consisting of $H_2$ and $Cu$ electrodes?

The Gibbs energy for the decomposition of $Al_2O_3$ at $500^oC$ is as follows:
$\frac{2}{3} Al_2O_3 \rightarrow \frac{4}{3} Al + O_2$
$\Delta_rG = +960 \ kJ \ mol^{-1}$
The potential difference needed for the electrolytic reduction of aluminium oxide $(Al_2O_3)$ at $500^oC$ is at least ........ $V$.

For the Galvanic cell:
$Ag_{(s)} \, | \, Ag_2C_2O_{4(s)} \, | \, C_2O_4^{2-} (0.02 \ M) \, || \, Ag^{+}(0.5 \ M) \, | \, Ag_{(s)}$
$EMF$ of the cell is $0.264 \ V$ at $25 \ ^oC$. The $K_{sp}$ of $Ag_2C_2O_{4(s)}$ is:
$[Given: \frac{2.303RT}{F} = 0.06, \ \log 2 = 0.3]$

When an acid cell is charged,then

Select the correct cell reaction for the cell $Pt_{(s)}|Cl_{2(g)}|Cl^{-}_{(aq)}||Ag^{+}_{(aq)}|Ag_{(s)}$.

The extent of charge of a lead accumulator is determined by