When a lead storage battery is charged:

Which of the following statements is true for fuel cells?

What is the function of a salt bridge?

$Cu^{+}_{(aq)}$ 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 $E^{\circ}_{Cu^{2+}/Cu^{+}} = 0.15 \ V$.

What is an electrolytic cell? Give its uses.

What is the density of a solution of sulphuric acid used as an electrolyte in lead accumulators (in $g \ mL^{-1}$)?