The three cells with their \(E^\circ_{\text{(cell)}}\) values are given below:
Cells | \(E^\circ_{\text{(cell)}}/V\) | |
(a) | Fe|Fe2+||Fe3+|Fe | 0.404 |
(b) | Fe|Fe2+||Fe3+, Fe2+|Pt | 1.211 |
(c) | Fe|Fe3+||Fe3+, Fe2+|Pt | 0.807 |
1. | –1.212 F, –1.211 F, –0.807 F |
2. | +2.424 F, +2.422 F, +2.421 F |
3. | –0.808 F, –2.422 F, –2.421 F |
4. | –2.424 F, –2.422 F, –2.421 F |
The number of Faradays (F) required to produce 20 g of calcium from molten CaCl2 (Atomic mass of Ca = 40 g mol–1) is:
1. 2
2. 3
3. 4
4. 1
During the electrolysis of molten sodium chloride, the time required to produce 0.10 mol of chlorine gas using a current of 3 amperes is:
1. 55 minutes
2. 110 minutes
3. 220 minutes
4. 330 minutes
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.
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
The weight of silver (at.wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of O2 at STP will be:
1. 5.4 g
2. 10.8 g
3. 54.0 g
4. 108.0 g
In producing chlorine by electrolysis, 100 kW power at 125 V is being consumed.
How much chlorine per minute is liberated:
(Given -ECE of chlorine is 0.367 X 10-6 kgC-1)
1.
2.
3.
4.
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 |
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