What is the change in oxidation number of $Pb$ at the positive electrode of a lead accumulator acting as a galvanic cell?

Which statement is incorrect for a galvanic cell?

Which of the following is $NOT$ true about a voltaic cell?

The minimum voltage (in $V$) required to bring about the electrolysis of $1 \ M$ copper$(II)$ sulphate solution at $298 \ K$ is (Given $E^{\circ}_{Cu^{2+}/Cu} = 0.34 \ V$ and $E^{\circ}_{O_2/H_2O} = 1.23 \ V$)

Identify the function of a salt bridge in an electrochemical cell.

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