Q. No.The number of electrons delivered at the cathode during electrolysis by a current of 1 ampere in 60 seconds is:
(Charge on electron = 1.60 × 10–19 C)
1.
2.
3.
4.
The pressure of H2 required to make the potential of H2 - electrode zero in pure water at 298 K is:
| 1. | 10–12 atm | 2. | 10–10 atm |
| 3. | 10–4 atm | 4. | 10–14 atm |
A device that converts the energy of combustion of fuels, like hydrogen and methane, directly into electrical energy is known as:
| 1. | Fuel cell. | 2. | Electrolytic cell. |
| 3. | Dynamo. | 4. | Ni-Cd cell. |
When 0.1 mol MnO42– is oxidized, the quantity of electricity required to completely oxidise MnO42– to MnO4– is:
1. 96500 C
2. 2 × 96500 C
3. 9650 C
4. 96.50 C
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. | \(1.25 \times10^{-4}\) |
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