On the basis of the information available from the reaction
4/3 Al + O2 → 2/3 Al2O3, ΔG = - 827 KJ mol-1 of O2 , the minimum emf required to carry out the electrolysis of Al2O3 is (F = 96500 C mol-1)
2.14 V
4.28 V
6.42 V
8.56 V
On heating one end of a piece of a metal, the other end becomes hot because of
Energised electrons moving to the other end
Resistance of the metal
Mobility of atoms in the metal
Minor perturbation cell in the energy of atoms .
EoFe2+/Fe = -0.441 V and EoFe3+/Fe2+ = 0.771 V,
the standard emf of the reaction
Fe + 2 Fe3+ → 3 Fe2+ will be
0.111 V
0.330 V
1.653 V
1.212 V
Which one of the following pairs of substances on reaction will not evolve H2 gas?
Iron and H2SO4 (aqueous)
Iron and Steam
Copper and HCl (aqueous)
Sodium and Ethyl alcohol
Standard electrode potentials are
Fe2+ / Fe, Eo = - 0.44 V
Fe3+ / Fe2+ , Eo = 0.77 V
Fe2+, Fe3+ and Fe block are kept together, then
Fe3+ increases
Fe3+ decreases
Fe2+/Fe3+ remains unchanged
Fe2+ decreases
The most convenient method to protect the bottom of the ship made of iron is
Coating it with red lead oxide
White tin plating
Connecting it with Mg block
Connecting it with Pb block
An electrochemical cell is shown below
Pt, H2 (1 atm) |HCl (0.1 M)| CH3COOH(0.1 M)| H2 (1 atm), Pt. the emf of the cell will not be zero, because
emf depends on molarities of acids used
pH of 0.1 M HCl and 0.1 M CH3COOH is not same
The temperature is constant
Acids used in two compartments are different
Equivalent conductance of NaCl, HCl and C2H5COONa at infinite dilution are 126.45, 426.16 and 91 ohm-1 cm2, respectively. The equivalent conductance of C2H5COOH is
201.28 ohm-1 cm2
390.71 ohm-1 cm2
698.28 ohm-1 cm2
540.48 ohm-1 cm2
The equivalent conductance of Ba2+ and Cl- are 127 and 76 ohm-1 cm-1 eq-1 respectively at infinite dilution. The equivalent conductance of BaCl2 at infinite dilution will be
139.52
203
279
101.5
Without losing its concentration ZnCl2 solution cannot be kept in contact with
Au
Al
Pb
Ag
