CBSE
Multiple Choice QuestionsThe efficiency of a fuel cell is given by:
Kohlrausch's law states that at
finite dilution, each ion makes a definite contribution to the equivalent conductance of an electrolyte, whatever be the nature of the other ion of the electrolyte.
infinite dilution, each ion makes a definite contribution to the equivalent conductance of an electrolyte depending on the nature of the other ion of the electrolyte.
infinite dilution, each ion makes a definite contribution to the conductance of an electrolyte whatever be the nature of the other ions of the electrolyte.
infinite dilution, each ion makes a definite contribution to the conductance of an electrolyte whatever be the nature of the other ions of the electrolyte.
Standard free energies of formation (in kJ/mol) at 298 K are -237.2, 394.4 and -8.2 for H2O (l), CO2 (g) and pentane (g), respectively. The value of Ecello for pentane-oxygen fuel cell is
1.968 V
2.0968 V
1.0968 V
1.0968 V
The values of ΔH and ΔSfor the reaction, C(graphite) + CO2 → 2 CO (g) are 170 kJ and 170 JK-1 respectively. This reaction will be spontaneous at
710 K
910 K
1110 K
1110 K
If 
the standard emf of the reaction:
Fe + 2 Fe3+ →3Fe2+
will be:
0.330 V
1.653 V
Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.5 x 104 An of current is passed through molten Al2O3 for 6h, what mass of aluminium is produced? (Assume 100% current efficiency, at.mass of Al = 27 g mol-1)
9.0 x 103 g
8.1 x 104 g
2.4 x 105 g
2.4 x 105 g
The equilibrium constant of the reaction:
Cu (s) + 2 Ag+ (aq) → Cu2+ (aq) + 2 Ag (s);
Eo = 0.46 V at 298 K
2.4 x 1010
2.0 x 1010
4.0 x 1010
4.0 x 1010
For vaporisation of water at 1 atm pressure, the values of ΔH and ΔS are 40.63 kJ mol- and 108.8 JK-1 mol-1, respectively. The temperature when Gibbs energy change (ΔG) for this transformation will be zero, is
273.14 K
393.4 K
373.4 K
373.4 K
The equivalent conductance of M/32 solution of weak monobasic acid is 8.0 ohm-cm2 and at infinite dilution is 400 ohm-cm2. The dissociation constant of this acid is
1.25 x 10-5
1.25 x 10-6
6.25 x 10-4
6.25 x 10-4
Given,
(i) Cu2+ + 2e- → Cu, Eo = 0.337 V
(ii) Cu2+ +e- → Cu+, Eo = 0.153
Electrode potential, Eo for the reaction,
Cu +e- →Cu, will be
0.52 V
0.90 V
0.30 V
0.30 V
