General
✓✗The electrode potentials for Cu2+(aq) + e− → Cu+(aq) and Cu+(aq) + e− → Cu(s) are +0.15 V and +0.50 V respectively. The value of E°(Cu2+/Cu) will be
- 0.150 V
- 0.500 V
- 0.325 V
- 0.650 V
General
✓✗The overpotential (overvoltage) of an electrode reaction is
- always zero for gases
- the emf of the cell
- the extra potential needed beyond the theoretical value to make the reaction occur at a reasonable rate
- the potential of the SHE
General
✓✗Given E°(Fe2+/Fe) = −0.44 V and E°(Cu2+/Cu) = +0.34 V, the standard emf of the cell Fe|Fe2+||Cu2+|Cu is
- 0.78 V
- 0.34 V
- 1.12 V
- 0.10 V
General
✓✗Which metal ion is the strongest oxidising agent? E°(Cr3+/Cr2+) = −0.41 V, E°(Mn3+/Mn2+) = +1.51 V, E°(Fe3+/Fe2+) = +0.77 V, E°(Co3+/Co2+) = +1.97 V
- Mn3+
- Fe3+
- Cr3+
- Co3+
General
✓✗The resistance of a 0.1 M KCl solution in a conductivity cell is 100 ohm. If the conductivity of the solution is 1.29 × 10−2 S cm−1, the cell constant is
- 12.90 cm−1
- 0.13 cm−1
- 1.29 cm−1
- 0.01 cm−1
General
✓✗A current of 0.5 A is passed for 2 hours through molten CaCl2. The mass of calcium deposited is (Ca = 40 g mol−1)
- 0.746 g
- 0.373 g
- 0.012 g
- 1.492 g
General
✓✗The quantity of electricity Q passed through a cell is given by
- Q = It
- Q = I/t
- Q = It2
- Q = V/I
General
✓✗For the cell Zn|Zn2+(1 M)||H+(1 M)|H2(1 bar)|Pt, the emf is 0.76 V. The standard reduction potential of zinc is
- +1.52 V
- 0.00 V
- −0.76 V
- +0.76 V
General
✓✗In the electrolysis of aqueous NaCl, H2 is liberated at a Pt cathode, while with an Hg cathode sodium amalgam is formed. The reason for this is
- the concentration of H+ ions is larger when a Pt electrode is taken
- Hg is more inert than Pt
- more voltage (overpotential) is required to reduce H+ at Hg than at Pt
- Na is dissolved in Hg while it does not dissolve in Pt
General
✓✗The mass of PbSO4 formed (at both electrodes together) when a lead storage battery delivers 2 F of charge is (PbSO4 = 303 g mol−1)
- 1212 g
- 606 g
- 303 g
- 152 g
General
✓✗Assertion: The H2−O2 fuel cell can have a thermodynamic efficiency of over 80%.
Reason: In a fuel cell the free energy of the reaction is converted directly into electrical energy.
Reason: In a fuel cell the free energy of the reaction is converted directly into electrical energy.
- Both Assertion and Reason are true and Reason is the correct explanation of Assertion
- Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- Assertion is true but Reason is false
- Both Assertion and Reason are false
General
✓✗For the disproportionation 3Au+ → Au3+ + 2Au, given E°(Au+/Au) = 1.69 V and E°(Au3+/Au+) = 1.40 V, E°cell is
- 1.55 V
- 3.09 V
- −0.29 V
- 0.29 V
General
✓✗The mass of carbon anode consumed (giving only carbon dioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (atomic mass: Al = 27)
- 180 kg
- 540 kg
- 270 kg
- 90 kg
General
✓✗In the electrolysis of an aqueous solution of KI with inert electrodes, the product at the anode is
- K
- I2
- O2
- H2
General
✓✗According to Faraday's second law, when the same quantity of electricity is passed through different electrolytes, the masses of substances liberated are proportional to their
- densities
- atomic numbers
- molar masses
- equivalent masses (molar mass/n)