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 element, which forms oxides in all oxidation states + 1 to +5, is
N
P
As
Sb
In the reaction A + e- →A-
A is readily oxidised
A is readily reduced
A- is readily oxidised
A- is readily reduced
The mass of copper deposited from a solution of CuSO4 by passing a current of 5 A for 15 min is (Atomic Wt. of copper = 63.5)
0.3 g
0.5 g
0.7 g
0.9 g
The pair of compounds, in which both the metals are in their highest possible oxidation state, is
[Fe(CN)6]3-
TiO3, MnO2
CrO2Cl2, MnO4-
[Co(CN)6]3-, MnO3
What is the oxidation number of iron in the compound [Fe(H2O)5(NO)+]2+
+ 1
+ 4
+ 5
+ 7
The oxidation number of Fe in Fe3O4 is
The amount of mercury deposited by passing 300 C of charge through mercurous sulphate solution is (Take atomic weight of mercury as 200)
0.2 g
0.4 g
0.6 g
0.8 g
Oxidation number of Os in OsO4 is
+ 6
+ 8
What is the oxidation number of sulphur in Na2S2O5?
2
3
4
7
