In which cell, free energy of a chemical reaction is directly converted into electricity?
fuel cell
lechlanche cell
concentration cell
lead storage battery
The current in a given wire is 1.8 A. A charge passed through the wire in 1.36 minutes is
100 C
147 C
247 C
347 C
Which of the following oxide, cannot act as a reducing agent?
NO2
SO2
CO2
ClO2
The highest electrical conductivity of the following aqueous solutions is of
0.1 M acetic acid
0.1 M chloroacetic acid
0.1 M fluoroacetic acid
0.1 M difluoroacetic acid
The oxidation number of chromium in potassium dichromate is
+ 2
- 2
- 5
+ 6
The standard e.m.f of a galvanic cell, with standard electrode potentials of zinc equal to -0.76 V and that of copper equal to + 0.34 V, is
+ 0.76 V
+ 1.1 V
- 0.34 V
- 1.1 V
The electrode potentials of half-cell reactions are: Zn → Zn2+ + 2e- ; E = -0.76 V and Fe → Fe2+ + 2e- ;E = 0.41 V. The e.m.f of cell Fe2+ + Zn →Zn2+ + Fe is
+ 1.17 V
+ 0.35 V
- 1.17 V
- 0.35 V
If 0.25 g of copper is deposited by a current of 0.2 ampere in 10 minutes, then the electrochemical equivalent of the copper is
0.2
0.02
0.002
0.0002
The standard e.m.f of a cell, involving one electron change is 0.591 V 25oC. The equilibrium constant of the reaction is (F = 96500 C-mol-1; R = 8.314 J - K-1 - mol-1)
1.0 × 101
1.0 ×105
1.0 ×1010
1.0 ×1030
During the electrolysis of fused sodium chloride, the anodic reaction is
oxidation of sodium ions
reduction of sodium ions
oxidation of chloride ions
reduction of chloride ions
