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)
Which of the following is the strongest oxidising agent?
BrO3-/Br2+ ; Eo = + 1.50
Fe3+/Fe2+ ; Eo = + 0.76
MnO4-/Mn2+ ; Eo = + 1.52
Cr2O72-/Cr3+ ; Eo = + 1.33
For the redox reaction : Zn(s) + Cu2+ (0.1 M) → Zn2+ (1 M) + Cu(s) taking place in a cell, Eo cell is 1.1 volt. Calculate the value of Ecell for the cell?
2.14 volt
1.80 volt
1.07 volt
0.82 volt
The charge on one electron is (Avogadro's number = 6.023 × 1023)
1 × 10-19 C
1.6 × 10-19 C
2.6 × 10-19 C
3.6 × 10-19 C
In the reaction : 14 H+ + Cr2O72- + 3Ni → 2Cr3+ + 7H2O + 3Ni2+, which of the following substance is a reducing agent?
H2O
Ni
H+
Cr2O72-
The amount of chlorine evolved, when 2 A of current is passed fro 30 minutes in an aqueous solution of NaCl will be
1.32 g
4.56 g
9.82 g
12.6 g
The oxidation number of nitrogen in NaNO2 is
-3
+ 3
- 5
+ 5
The EoM3+/M2+ values for Cr, Mn, Fe and Co are -0.41 V, + 1.57 V, +0.77 V and +1.97 V respectively. For which one of the metals, the change in oxidation state from +2 to +3 will be easiest?
Cr
Co
Fe
Mn
HNO2 acts both as reductant and oxidant, while HNO3 acts only as oxidant. Why?
solubility ability
maximum oxidation number
minimum oxidation number
minimum number of valence electron
The oxidation number of chromium in potassium dichromate is
+ 2
- 2
+ 6
