CBSE
Multiple Choice QuestionsStandard 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
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.
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
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
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
If 
the standard emf of the reaction:
Fe + 2 Fe3+ →3Fe2+
will be:
0.330 V
1.653 V
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 efficiency of a fuel cell is given by:
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
