General
✓✗Given E°(Fe3+/Fe2+) = 0.77 V, E°(Fe2+/Fe) = −0.44 V, E°(Cu2+/Cu) = 0.34 V and E°(Cu2+/Cu+) = 0.15 V. Which of the following reactions is NOT spontaneous?
- Fe2+ + Cu → Fe + Cu2+
- Fe + Cu2+ → Fe2+ + Cu
- Fe + 2Fe3+ → 3Fe2+
- 2Fe3+ + Cu → 2Fe2+ + Cu2+
General
✓✗The number of faradays required to reduce 1 mol of Cr2O72− to Cr3+ is
- 2
- 6
- 3
- 12
General
✓✗The reduction potential of a hydrogen electrode in pure water (pH2 = 1 bar) at 298 K is
- 0.413 V
- −0.826 V
- 0.000 V
- −0.413 V
General
✓✗The strongest oxidising agent in the electrochemical series is
- Cl2
- Li+
- H+
- F2
General
✓✗The emf of the cell Zn|Zn2+(0.1 M)||Cu2+(1 M)|Cu at 298 K is (E°cell = 1.10 V)
- 1.100 V
- 1.130 V
- 1.071 V
- 1.159 V
General
✓✗The degree of dissociation of a weak acid whose molar conductivity is 39 S cm2 mol−1 and limiting molar conductivity is 390 S cm2 mol−1 is
- 0.10
- 0.39
- 1.00
- 0.01
General
✓✗The electrode potential of a silver electrode in 0.001 M AgNO3 at 298 K is (E°(Ag+/Ag) = 0.80 V)
- 0.977 V
- 0.623 V
- 0.800 V
- 0.712 V
General
✓✗The charge required to convert 1 mol of Fe3O4 completely to Fe2O3 is
- 2 F
- 3 F
- 1 F
- 0.5 F
General
✓✗The limiting molar conductivities of Ba2+ and Cl− ions are 127 and 76 S cm2 mol−1 respectively. The limiting molar conductivity of BaCl2 is
- 203 S cm2 mol−1
- 101.5 S cm2 mol−1
- 279 S cm2 mol−1
- 139.5 S cm2 mol−1
General
✓✗The variation of molar conductivity with concentration for a weak electrolyte is mainly due to
- a decrease in the number of ions
- an increase in ionic mobility only
- the change in cell constant
- an increase in the degree of dissociation on dilution
General
✓✗On heating one end of a piece of metal, the other end becomes hot because of
- energised electrons moving to the other end
- minor perturbation in the energy of atoms
- the mobility of atoms in the metal
- the resistance of the metal
General
✓✗In electrorefining of copper, the impure copper is made the
- cathode
- electrolyte
- anode
- salt bridge
General
✓✗A current of 1.5 A for 10 minutes deposits 0.45 g of a metal of molar mass 96.5 g mol−1. The charge on the metal ion is
- +2
- +4
- +1
- +3
General
✓✗The resistance of a conductivity cell filled with 0.1 M KCl (κ = 1.29 S m−1) is 100 ohm. When filled with 0.02 M KCl, the resistance is 520 ohm. The molar conductivity of 0.02 M KCl is
- 248.0 S cm2 mol−1
- 645.0 S cm2 mol−1
- 124.0 S cm2 mol−1
- 12.4 S cm2 mol−1
General
✓✗The resistance of a conductivity cell is measured using
- a voltmeter only
- a DC source
- an AC source (Wheatstone bridge) to avoid electrolysis
- a galvanometer with DC