22338.20 ml solution of 0.1 M ferrous sulphate was completely oxidised using a suitable oxidising agent. What is the number of electrons exchanged?
1.204 × 1022
193
1930
1.204 × 1021
22339.The process of zinc–plating on iron sheet is known as
galvanization
roasting
annealing
smelting
22340.The logarithm of the equilibrium constant of the cell reaction corresponding to the cell X(s) | X2+(aq) || Y+(aq) | Y(s) with standard cell potential, Eo
Cell = 1.2 V is given by
Cell = 1.2 V is given by
12.5
21.5
40.5
47.5
22341.The pH of aqueous KCl solution is 7.0. This solution was electrolyzed for a few seconds using Pt electrodes. Which of the following is correct?
The pH of solution decreases
The pH of solution increases
Cl2 is liberated at cathode
The pH of solution remains the same
22342.The standard EMF of Daniell cell is 1.10 volt. The maximum electrical work obtained from the Daniell cell is
212.3 kJ
175.4 kJ
106.15 kJ
53.07 kJ
22343.The standard potentials at 25°C for the half reactions are given against them below.
Zn2++ 2e– → Zn; E° = –0.762 V
Mg2++ 2e– →Mg E° = –2.37 V
When Zinc dust is added to MgCl2 solutionMagnesium is precipitated
Zinc dissolves in the solution
Zinc chloride in formed
No reaction takes place
22344.On the basis of information available for the reaction:
$\dfrac{4}{3}$Al + O2 → 2Al2O3; ΔG = –827 kJ mol–1 of O2.
The minimum e.m.f. 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
22345.The standard reduction potential for Cu2+/Cu; Zn2+/Zn; Li+/Li; Ag+/Ag and H+/H2 are 0.34 V, –0.762 V, –3.05 V, + 0.80 V and 0.00 V respectively. Choose the strongest reducing agent among the following.
Zn
H2
Ag
Li
22346.The standard reduction potentials of Ag, Cu, Co and Zn are 0.799, 0.337, –0.277 and –0.762 V respectively. Which of the following cells will have maximum cell e.m.f.?
Zn | Zn+2(1M) || Cu2+ (1M) | Cu
Zn | Zn2+(1M) || Ag+ (1M) | Ag
Cu | Cu2+(1M) || Ag+ (1M) | Ag
Zn | Zn2+(1M) || Co2+ (1M) | Co
22347.The Eo
M3+/m2+values of Cr, Mn, Fe and Co are –0.41, + 1.57, +0.77 and +1.97 V respectively. For which one of these metals the change in oxidation state from +2 to +3 is easiest?
M3+/m2+values of Cr, Mn, Fe and Co are –0.41, + 1.57, +0.77 and +1.97 V respectively. For which one of these metals the change in oxidation state from +2 to +3 is easiest?
Cr
Mn
Fe
Co