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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 Ka 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

Subtopic:  Relation between Emf, G, Kc & pH |
 62%
Level 2: 60%+
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A dilute solution of H2SO4 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

Subtopic:  Faraday’s Law of Electrolysis |
 53%
Level 3: 35%-60%
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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

Subtopic:  Electrode & Electrode Potential |
 76%
Level 2: 60%+
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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?

1. M + X → M⁺ + X⁻ is spontaneous.
2. M⁺ + X⁻ → M + X is spontaneous.
3. E°cell = 0.77 V
4. E°cell = −0.77 V

Subtopic:  Electrode & Electrode Potential |
 67%
Level 2: 60%+
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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 10-1Sm-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

Subtopic:  Conductance & Conductivity |
 75%
Level 2: 60%+
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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

Subtopic:  Faraday’s Law of Electrolysis |
Level 3: 35%-60%
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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 C3H8(g),H2O(l)andCO2(g) are -23.5, -237.2 and -394.4 kJmol-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

Subtopic:  Relation between Emf, G, Kc & pH |
 53%
Level 3: 35%-60%
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The temperature coefficient of a standard Cd-cell is 5.0×10-5Vk-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

Subtopic:  Relation between Emf, G, Kc & pH |
 65%
Level 2: 60%+
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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.

Subtopic:  Faraday’s Law of Electrolysis |
 60%
Level 2: 60%+
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The standard reduction potential of a silver chloride electrode is 0.2 V and that of a silver electrode is 0.79 V. The maximum amount of AgCl that can dissolve in 106Lofa0.1MAgNO3 solution is 

(1) 0.5 mmol                                              

(2) 1.0 mmol

(2) 2.0 mmol                                             

(4) 2.5 mmol

Subtopic:  Relation between Emf, G, Kc & pH |
 67%
Level 2: 60%+
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