Consider the following relations for emf of an electrochemical cell:
| (a) | emf of a cell = (Oxidation potential of the anode) – (Reduction potential of the cathode) |
| (b) | emf of a cell = (Oxidation potential of the anode) + (Reduction potential of the cathode) |
| (c) | emf of a cell = (Reduction potential of the anode) + (Reduction potential of the cathode) |
| (d) | emf of a cell = (Oxidation potential of the anode) – (Oxidation potential of the cathode) |
Which of the following combinations correctly represents the relation for the emf of the cell?
| 1. | (a) and (b) | 2. | (c) and (d) |
| 3. | (b) and (d) | 4. | (c) and (a) |
The correct expression that represents the equivalent conductance at infinite dilution of is:
(Given that are the equivalent conductances at infinite dilution of the respective ions)
1.
2.
3.
4.
Molar conductivities at infinite dilution of
NaCl, HCl, and are 126.4, 425.9, and 91.0 S cm2 mol–1 respectively.
for will be:
| 1. | \(180.5~S~cm^2~mol^{-1}\) | 2. | \(290.8~S~cm^2~mol^{-1}\) |
| 3. | \(390.5~S~cm^2~mol^{-1}\) | 4. | \(425.5~S~cm^2~mol^{-1}\) |
The Gibb's energy for the decomposition of \(\mathrm{A l_{2} O_{3}}\) at \(\mathrm{500~ ^\circ C}\) is as follows:
2/3Al2O3 → 4/3Al + O2 ; ∆rG = + 960 k J mol–1
The potential difference needed for the electrolytic reduction of aluminium oxide (Al2O3) at \(\mathrm{500~ ^\circ C}\) is at least,
1. 3.0 V
2. 2.5 V
3. 5.0 V
4. 4.5 V
What is the mass of silver deposited when the charge passed is doubled, if a charge of \(10^5\) coulomb deposits 1 g of Ag?
| 1. | 1 gm | 2. | 2 gm |
| 3. | 3 gm | 4. | 4 gm |
The concentration of solution will change when it is placed in a container which is made of:
| 1. | Al | 2. | Cu |
| 3. | Ag | 4. | None |
Which of the following quantities does the change in Gibbs free energy (ΔG) depend upon, for the electrochemical cell reaction: \(Cu^{2+}(C_{1}) + Zn \to Cu + Zn^{2+}(C_{2})\)
\(1. \ ln (C_{1}+C_{2})\)
2. \(ln (\frac{C_{2}}{C_{1}})\)
\(3. \ ln C_{2}\)
\(4. \ lnC_{1}\)
4.5 g of aluminium (at. mass = 27 amu) is deposited at cathode from Al3+ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H+ ions in solution by the same quantity of electric charge will be:
| 1. | 44.8 L | 2. | 11.2 L |
| 3. | 22.4 L | 4. | 5.6 L |
For the disproportionation of copper:
2Cu+ → C u2+ + C u is:
(Given for Cu+2/Cu is 0.34 V & Eº for Cu+2/Cu+ is 0.15 V )
1. 0.49 V
2. – 0.19 V
3. 0.38 V
4. – 0.38 V
A cell reaction become spontaneous when:
1. ∆Gº is negative
2. ∆Gº is positive
3. is positive
4. is negative