Molar conductivity of ionic solution depends on ........... .
For the given cell, $\mathrm{Mg}\left|\mathrm{Mg}^{2+} \| \mathrm{Cu}^{2+}\right| \mathrm{Cu}$
Can absolute electrode potential of an electrode be measured?
No, only the difference in potential between two electrodes can be measured. This is due to the reason that oxidation or reduction cannot occur alone. So, when we measure electrode potential of any electrode we have to take a reference electrode.
Can $E_{\text {cell }}^{\circ}$ or $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}$ for cell reaction ever be equal to zero ?
No, otherwise the reaction become non-feasible.
The reaction is feasible only at $E_{\text {cell }}^{\circ}=$ positive or $\Delta_r G^{\circ}=$ negative .
when $E^{\circ}=\Delta_r G^{\circ}=0$ the reaction reaches at equilibrium.
Under what condition is $E_{\text {cell }}=0$ or $\Delta_r G=0$ ?
At the stage of chemical equilibrium in the cell.
$$\begin{aligned} E_{\text {cell }} & =0 \\ \Delta_r G^{\circ} & =-n F E_{\text {cell }}^{\circ} \\ & =-n \times F \times 0=0 \end{aligned}$$