What advantage do the fuel cells have over primary and secondary batteries?

$Cu^{+}_{(aq)}$ is unstable in solution and undergoes simultaneous oxidation and reduction,according to the reaction $2 Cu^{+}_{(aq)} \rightleftharpoons Cu^{2+}_{(aq)} + Cu_{(s)}$. Choose the correct $E^{\circ}$ for the above reaction if $E^{\circ}_{Cu^{2+}/Cu} = 0.34 \ V$ and $E^{\circ}_{Cu^{2+}/Cu^{+}} = 0.15 \ V$.

$A$ metal used in storage batteries is

The standard electrode potential of $Zn^{2+}/Zn$ is $-0.76\, V$ and that of $Cu^{2+}/Cu$ is $0.34\, V$. The emf $(V)$ and the free energy change $(kJ\, mol^{-1})$,respectively for a Daniell cell will be

Mark the false statement.

The extent of charge of a lead accumulator is determined by