The efficiency of a fuel cell is given by:

$\left(\mathrm{a}\right) ∆\mathrm{H}/∆\mathrm{G} \left(\mathrm{b}\right) ∆\mathrm{G}/∆\mathrm{S}$
$\left(\mathrm{c}\right) ∆\mathrm{G}/∆\mathrm{H} \left(\mathrm{d}\right) ∆\mathrm{S}/∆\mathrm{G}$

A hypothetical electrochemical cell is shown below A l A⁺ (xM)l l B⁺ (yM) l B
The Emf measured is +0.20 V.The cell reaction is:-
(1) A⁺ + B → A + B⁺

(2) A⁺ + e^- →  A ; B⁺ + e^- → B

(3) the cell reaction cannot be predicted

(4) A + B⁺ → A⁺ + B

Based on the given data, what is the value of the molar conductivity at infinite dilution (Λm^∞) for SrCl₂ in water at 25°C?

1. 270

2. 260

3. 250

4. 255

During electrolysis of conc. H₂SO₄, perdisulphuric acid (H₂S₂O₈), and O₂ form in equimolar amount. The amount of H₂ that will form simultaneously will be : 

1. Thrice that of O₂ in moles.

2. Twice that of O₂ in moles.

3. Equal to that of O₂ in moles.

4. Half of that of O₂ in moles.

Limiting molar conductivity of NH₄OH (i.e Åm(NH₄OH)) is equal to:-

1. Å_m (NH₄Cl)+Å_m(NaCl)-Å_m(NaOH) 

2. Å_m(NaOH)+Å_m(NaCl)-Å_m(NH₄Cl)

3. Å_m(NH₄OH)+Å_m(NH₄Cl)-Å_m(HCl)

4. Å(NH₄Cl)+Å(NaOH)-Å(NaCl)

A button cell used in watches functions as following

Zn(s) + Ag₂O(s) + H₂O (l) $\rightleftharpoons$2Ag(s) + Zn²⁺(aq) + 2OH^-(aq)

If half cell potentials are

$$\begin{gathered} {{\mathrm{Zn}}^{2+}}_{\left(\mathrm{aq}\right)} +\hspace{0.17em}2{\mathrm{e}}^{-} \to {\mathrm{Zn}}_{\left(\mathrm{x}\right)}; {\mathrm{E}}^{\mathrm{o}} = -0.76\mathrm{V} \\ {\mathrm{Ag}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)} + {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} + 2{\mathrm{e}}^{-} \to 2{\mathrm{Ag}}_{\left(\mathrm{s}\right)} + 2{{\mathrm{OH}}^{-}}_{\left(\mathrm{aq}\right)}; \\ {\mathrm{E}}^{\mathrm{o}} = 0.34\mathrm{V} \end{gathered}$$

The cell potential will be

1. 0.84 V

2. 1.34 V

3. 1.10 V

4. 0.42 V

Electrolysis of hot aqueous solution of NaCl gives NaClO₄ as-

$\mathrm{NaCl} +\hspace{0.17em}4{\mathrm{H}}_2\mathrm{O} \stackrel{ }{\to }{\mathrm{NaClO}}_4 + 4{\mathrm{H}}_2$

How many faraday are required to obtain 1000 g of sodium perchlorate ?

(1) 66 F

(2) 122.5 F

(3) 15.13 F

(4) 1.86 F

The quantity of electricity required to reduce 12.3 g of nitrobenzene to aniline with 50 % current efficiency is:

1. 1 F

2. 0.6 F

3. 0.5 F

4. 1.2 F

When NaCl solution is electrolysed using Pt electrodes then pH of solution

1. Increases

2. Decreases

3. Remains same

4. Firstly increases and then decreases

What is the value of ${\mathrm{pK}}_{\mathrm{b}} ({\mathrm{CH}}_3{\mathrm{COO}}^{-} )$ if ${\mathrm{\lambda }}_{\mathrm{m}}^0= 390 \& {\mathrm{\lambda }}_{\mathrm{m}} = 7.8$ for 0.04 of a ${\mathrm{CH}}_3\mathrm{COOH}$  at $25°\mathrm{C}$ ?

(A) 9.3                                               

(B) 9.2

(C) 4.7                                               

(D) 4.8