Pairs of reactants (R) and product (P) are given below. The pair which can be used in a fuel cell is :

1. $R\mathit{=}{H}_{\mathit{2}\mathit{\left(}\mathit{g}\mathit{\right)}}\mathit{,}{O}_{\mathit{2}\mathit{\left(}\mathit{g}\mathit{\right)}}\mathit{;}P\mathit{=}{H}_{\mathit{2}}{O}_{\mathit{2}\mathit{\left(}\mathit{g}\mathit{\right)}}$

2. $\mathrm{R}={\mathrm{H}}_{2\left(\mathrm{g}\right)},{\mathrm{O}}_{2\left(\mathrm{g}\right)};\mathrm{P}={\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{\ell }\right)}$

3. $\mathrm{R}={\mathrm{H}}_{2\left(\mathrm{g}\right)},{\mathrm{O}}_{2\left(\mathrm{g}\right)},{\mathrm{Cl}}_{2\left(\mathrm{g}\right)};\mathrm{P}={\mathrm{HClO}}_{4\left(\mathrm{aq}\right)}$

4. $\mathrm{R}={\mathrm{H}}_{2\left(\mathrm{g}\right)},{\mathrm{N}}_{2\left(\mathrm{g}\right)};\mathrm{P}={\mathrm{NH}}_{3\left(\mathrm{aq}\right)}$

Molten sodium chloride conducts electricity due to the presence of: 

1. Free ions.

2. Free molecules.

3. Free electrons.

4. Atoms of sodium and chlorine.

The resistance of a cell containing 0.001 M KCl solution at 298 K is 1500 Ω. The conductivity is 0.146 × 10^–3 S cm^–1. The cell constant would be:

The amount of charge required for the reduction of 1 mol of ${\mathrm{MnO}}_4^{-}$ to ${\mathrm{Mn}}^{2+}$ is:

$1.$ $4.8$ $\times$ ${10}^5$ $\mathrm{C}$
$2.$ $3.2$ $\times$ ${10}^6$ $\mathrm{C}$
$3.$ $1.8$ $\times$ ${10}^5$ $\mathrm{C}$
$4.$ $4.1$ $\times$ ${10}^4$ $\mathrm{C}$

On electrolysis of dilute sulphuric acid using Platinum (Pt) electrode, the product obtained at the anode will be:

1. Oxygen gas

2. ${\mathrm{H}}_2\mathrm{S}$ gas

3. ${\mathrm{SO}}_2$ gas

4. Hydrogen gas 

The electrode potential for the Mg electrode varies according to the equation:

\(E_{Mg^{2+}/Mg}\ = \ E_{Mg^{2+}/Mg}^{o} \ - \ \frac{0.059}{2}log\frac{1}{[Mg^{2+}]}\) 

The graph of E_{Mg²⁺ / Mg} vs log [Mg²⁺] among the following is:

1.		2.
3.		4.

The correct statement among the following options is: 

The incorrect statement about an inert electrode in a cell is:

The cell constant of a conductivity cell-