In a half-cell containing \(\left[T l^{3+}\right]=0.1 M \text { and }\left[T l^{+}\right]=0.01 \mathrm{M},\) the cell potential is – 1.2496 V for the reaction \(T l^{+} \rightarrow T l^{3+}+2 e^{-}\). The standard reduction potential of the \(T l^{+} / T l^{3+}\) couple at  25 ° C is :

1.   1.44 V                                          
2.   0.61 V
3.   2.44 V                                          
4.   1.22 V

Given cell: 

Pt(s)|H₂(g)(P = 1 atm)| CH₃COOH(0.1 M), HCl(0.1 M) || KCl(aq)|Hg₂Cl₂(s)|Hg

EMF of the cell is found to be 0.045 V at 298 K and the temperature coefficient is 3.4×10^-4 V K^-1. The cell entropy change of the following cell is : 

[Given K_a CH₃COOH = 10^-5  M]

1. 70.8 J K⁻¹ mol⁻¹                      

2. 65.2 J K⁻¹ mol⁻¹

3. 79.2 J K⁻¹ mol⁻¹                  

4. 83.5 J K⁻¹ mol⁻¹

A dilute solution of $H_2<mspace\; width="1em"></mspace>S{O}_4$ was electrolysed by passing a current of 2 amp. The time required for formation of 0.5 mole of oxygen is :

1.   26.8 hours                                    

2.   13.4 hours

3.   6.7 hours                                      

4.   28.6 hours

The standard reduction potentials of Mn³⁺/Mn²⁺ and MnO₂/Mn³⁺ couples in acidic medium at 25°C are 1.50 V and 1.00 V, respectively. For the reaction:

2Mn³⁺ + 2H₂O → Mn²⁺ + MnO₂ + 4H⁺.

Find the nature of the reaction:

1.  Reversible                                             

2.  Non-spontaneous

3.  Spontaneous                                         

4.  Irreversible

Consider the electrochemical cell at 25 °C:

M | M⁺ || X⁻ | X

The standard reduction potentials are:

E°(M⁺/M) = 0.52 V
E°(X/X⁻) = 0.42 V

Which of the following statements is correct?

If a 100 mL solution of 0.1M HBr is titrated using a very concentrated solution of NaOH, when the conductivity (specific conductance) of the solution at the equivalence point will be:
Calculate your answer in terms of ${10}^{-1}S{m}^{-1}$
(Assume volume change is negligible due to addition of NaOH).
\(\text { Given } \wedge^{\circ} \mathrm{Na}^{+}=8 \times 10^{-3} \mathrm{S~m}^2 \mathrm{~mol}^{-1}; \wedge^{\circ}{ }_{\mathrm{Br}}=4 \times 10^{-3} \mathrm{~S} \mathrm{~m}^2 \mathrm{~mol}^{-1}\)

1.   6                               
2.   12
3.   15                             
4.   24

The volume of gases liberated at STP when a charge of 2F is passed
through aqueous solution of sodium phosphate, is :

1. 11.2L                                           

2. 44.8L

3. 33.6L                                           

4. 22.4L

It is desired to convert the energy derived from the combustion of propane into electrical energy, via a fuel cell. Given that the standard free energies of formation of $C_3{H}_8<mspace\; width="1em"></mspace>\left(g\right),<mspace\; width="1em"></mspace>H_{2}O\left(l\right)<mspace\; width="1em"></mspace>and<mspace\; width="1em"></mspace>C{O}_2<mspace\; width="1em"></mspace>\left(g\right)$ are -23.5, -237.2 and -394.4 $kJ<mspace\; width="1em"></mspace>mo{l}^{-1}$ respectively, calculate the standard EMF of the propane fuel cell.

1.   1.10 V                                           
2.   2.10 V
3.   3.12 V                                           
4.   4.12 V

The temperature coefficient of a standard Cd-cell is $–5.0<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^{-5}<mspace\; width="1em"></mspace>V{k}^{-1}$ whose emf at $25°C$ is 1.018 V. During the cell operation, the temperature will -

(1) increase                                      

(2) decreases

(3) either                                         

(4) remains constant

Na-amalgam is prepared by electrolysis of NaCl solution using liquid Hg as a cathode. How long should the current of 10 amp. is passed to produce 10% Na – Hg on a cathode of 10 gm Hg. (atomic mass of Na = 23).

1.   7.77 min.                                               
2.   9.44 min.
3.   5.24 min.                                               
4.   11.39 min.