Which of the following changes occurs during the discharging of a lead accumulator?

The electrochemical cell is set up as follows: $Pt (H_2, 1 \, atm) | HCl (0.1 \, M) || \text{Acetic Acid} (0.1 \, M) | (H_2, 1 \, atm) Pt$. The $E.M.F.$ of the cell is not zero because:

Which of the following is $NOT$ a 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 $E^{\circ}_{Cu^{2+}/Cu^{+}} = 0.15 \ V$.

For the reaction $2 Fe^{3+}_{(aq)} + 2 I^{-}_{(aq)} \rightarrow 2 Fe^{2+}_{(aq)} + I_{2(s)}$,the magnitude of the standard molar free energy change,$\Delta_{r} G_{m}^{\circ} = -$ ........... $kJ$ (Round off to the Nearest Integer). $\left[ E_{Fe^{2+} / Fe_{(s)}}^{\circ} = -0.440 \ V; \ E_{Fe^{3+} / Fe_{(s)}}^{\circ} = -0.036 \ V; \ E_{I_{2} / 2I^{-}}^{\circ} = 0.539 \ V; \ F = 96500 \ C \ mol^{-1} \right]$

$A$ solution containing $1 \ mol \ L^{-1}$ of each $Cu(NO_3)_2, AgNO_3, Hg_2(NO_3)_2$ and $Mg(NO_3)_2$ is being electrolysed using inert electrodes. The standard reduction potentials are $E^0_{Ag^{+}/Ag} = +0.80 \ V, E^0_{Hg_2^{2+}/Hg} = +0.79 \ V, E^0_{Cu^{2+}/Cu} = +0.34 \ V, E^0_{Mg^{2+}/Mg} = -2.37 \ V$. With increasing voltage,the sequence of deposition of metals on the cathode will be: