Q. No.A hydrogen gas electrode is made by dipping platinum wire in a solution of HCl of pH = 10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of the electrode would be:
1.
0.59 V
2.
0.118 V
3.
1.18 V
4.
0.059 V
Zn(s) + Ag2O(s) + H2O(l) \(\rightleftharpoons\) 2Ag(s) + Zn2+(aq) + 2OH–(aq)
If half-cell potentials are-
| Zn2+(aq) + 2e–→ Zn(s) | Eo = – 0.76 V |
| Ag2O(s) + H2O(l) + 2e– → 2Ag(s) + 2OH–(aq) |
Eo = 0.34 V |
The cell potential will be:
| 1. | 0.42 V | 2. | 0.84 V |
| 3. | 1.34 V | 4. | 1.10 V |
| Cu2+(aq) + e- → Cu+(aq) | 0.15 V |
| Cu+(aq) + e- → Cu(s) | 0.50 V |
The value of \(E_{Cu^{2+}/Cu}^{o}\) will be:
| 1. | 0.325 V | 2. | 0650 V |
| 3. | 0.150 V | 4. | 0.500 V |
For the reduction of silver ions with copper metal, the standard cell potential was found to be +0.46 V at 25 °C. The value of standard Gibbs energy, ΔGo will be:
(F = 96500 C mol-1)
1. -89.0 kJ
2. -89.0 J
3. -44.5 kJ
4. -98.0 kJ
Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.0 x 104 A of current is passed through molten Al2O3 for 6 hours, the mass of aluminum produced is:
(Assume 100 % current efficiency, the atomic mass of Al = 27 g mol-1)
| 1. | 9.0 x 103 g | 2. | 8.1 x 104 g |
| 3. | 2.4 x 105 g | 4. | 1.3 x 104 g |
The molar conductance of solution of a weak monobasic acid is 8.0 ohm-1 cm2 and at infinite dilution is 400 ohm-1 cm2. The dissociation constant of this acid is:
| 1. | \(1.25 \times10^{-5}\) | 2. | \(1.25 \times10^{-6}\) |
| 3. | \(6.25 \times10^{-4}\) | 4. | \(1.25 \times10^{-4}\) |
Given:
(i) Eo = 0.337 V
(ii) Eo = 0.153 V
Electrode potential, Eo for the reaction,
, will be:
1. 0.52 V
2. 0.90 V
3. 0.30 V
4. 0.38 V
Kohlrausch's law states that at:
| 1. | Finite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte. |
| 2. | Infinite dilution, each molecule makes definite contribution to equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte. |
| 3. | Finite dilution, each molecule makes definite contribution to conductance of an electrolyte whatever be the nature of the other ion of the electrolyte. |
| 4. | Infinite dilution, each ion makes definite contribution to equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte. |
| 1. | K+> Na+> Rb+> Cs+ | 2. | Cs+> Rb+> K+> Na+ |
| 3. | Rb+> K+> Cs+> Na+ | 4. | Na+> K+> Rb+> Cs+ |
A steady current of 1.5 A flows through a copper voltmeter for 10 min. If the electrochemical equivalent of copper is 30 × 10-5 g C-1, the mass of copper deposited on the electrode will be:
1. 0.40 g
2. 0.50 g
3. 0.67 g
4. 0.27 g
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