Which of the following reaction is used to make a fuel cell?
2H2(g) + O2(g) → 2H2O(I)
2Fe(s) + O2(g) + 4H+(aq) → 2Fe2+(aq) + 2H2O(I)
Pb(s) + PbO2(s) + 2H2SO4(aq) →2PbSO4(s) + 2H2O(I)
Cd(s) + 2Ni(OH)3(s) → CdO(s) + 2Ni(OH)2(s) + H2O(I)
The charge required to liberate 112 ml of hydrogen from acidified water is
0.1 F
2 F
965 C
96500 C
The specific conductance of a normal solution of KCl at 25oC is 0.003 Ω-1-cm-1 If cell constant is 1.2 cm-1 , then resistance of a cell, containing this solution, will be
100 Ω
200 Ω
300 Ω
400 Ω
For standard reduction potentials of three metals A, B and C are +0.5 V, -3.0 V and -1.2 V respectively. The reducing powers of these metals are
B > C > A
A > B > C
C > B > A
A > C > B
In the reaction : Ag2O + H2O2 → 2Ag + H2O + O2, the H2O2 acts as
reducing agent
oxidising agent
bleaching agent
none of these
The e.m.f. of a cell prepared by combining Al/Al+3 and Ag/Ag+ is 2.46 V. The reduction potential of the silver electrode is + 0.80 V. The reduction potential of the aluminium electrode is
+ 1.66 V
- 3.26 V
+ 3.26 V
- 1.66 V
When 1 Faraday current is passed, which of the following would deposit 1g atomic weight of the metal?
NaCl
BaCl2
AlCl3
CuSO4
The time required to deposit one millimole of aluminium metal from Al2O3, by passing 9.65 amperes through solution of aluminium ion is
30 s
10 s
30,000 s
10,000 s
The mass of copper deposited from a solution of Cu2S by passing a current of 2.5 ampere for 6 minute is
0.3 g
0.5 g
0.7 g
0.9 g
Which of the following element shows maximum number of oxidation states in its compounds?
Eu
La
Gd
Np
