During the electrolysis of concentrated $H_2SO_4$,perdisulphuric acid $(H_2S_2O_8)$ and $O_2$ are formed at the anode in equimolar amounts. The moles of $H_2$ that will form simultaneously at the other electrode will be (Given: $2H_2SO_4 \rightarrow H_2S_2O_8 + 2H^+ + 2e^-$)

The rusting of iron takes place as follows. Calculate $\Delta G^o$ for the net process in $kJ \ mol^{-1}$.
$2H^{+} + 2e^- + \frac{1}{2}O_2 \longrightarrow H_2O_{(l)} ; E^o = +1.23 \ V$
$Fe^{2+} + 2e^- \longrightarrow Fe_{(s)} ; E^o = -0.44 \ V$

Chemical reactions involve the interaction of atoms and molecules. $A$ large number of atoms/molecules (approximately $6.023 \times 10^{23}$) are present in a few grams of any chemical compound,varying with their atomic/molecular masses. To handle such large numbers conveniently,the mole concept was introduced. This concept has implications in diverse areas such as analytical chemistry,biochemistry,electrochemistry,and radiochemistry. The following example illustrates a typical case involving a chemical/electrochemical reaction,which requires a clear understanding of the mole concept. $A$ $4.0 \ M$ aqueous solution of $NaCl$ is prepared and $500 \ mL$ of this solution is electrolysed. This leads to the evolution of chlorine gas at one of the electrodes (atomic mass: $Na=23, Hg=200; 1 \ F = 96500 \ C$).
$1.$ The total number of moles of chlorine gas evolved is:
$(A)$ $0.5$ $(B)$ $1.0$ $(C)$ $2.0$ $(D)$ $3.0$
$2.$ If the cathode is a $Hg$ electrode,the maximum weight $(g)$ of amalgam formed from this solution is:
$(A)$ $200$ $(B)$ $225$ $(C)$ $400$ $(D)$ $446$
$3.$ The total charge (coulombs) required for complete electrolysis is:
$(A)$ $24125$ $(B)$ $48250$ $(C)$ $96500$ $(D)$ $193000$

Which one of the following statements is correct?

The standard electrode potential $E^{\ominus}$ and its temperature coefficient $\left( \frac{dE^{\ominus}}{dT} \right)$ for a cell are $2 \ V$ and $-5 \times 10^{-4} \ V \ K^{-1}$ at $300 \ K$ respectively. The cell reaction is
$Zn_{(s)} + Cu^{2+}_{(aq)} \rightleftharpoons Zn^{2+}_{(aq)} + Cu_{(s)}$
Standard reaction enthalpy $\left( \Delta_r H^{\ominus} \right)$ is ....... $kJ$

At $298 \, K$, the standard Gibbs free energy of formation for $H_2O_{(l)}$, $CO_{2(g)}$, and $C_5H_{12(g)}$ are $-237.2$, $-394.4$, and $-8.2 \, kJ \, mol^{-1}$ respectively. What is the potential of a pentane-oxygen fuel cell in $V$?