22278.The half cell reaction, with its standard reduction potentials are:
(i) Pb2++ 2e– → Pb (E° = –0.13 V)
(ii) Ag++ e– → Ag (E° = +0.80 V)
Which ofthe following reactions will occur?
(i) Pb2++ 2e– → Pb (E° = –0.13 V)
(ii) Ag++ e– → Ag (E° = +0.80 V)
Which ofthe following reactions will occur?
Pb2++ 2Ag → 2Ag+ + Pb
Pb2++ H2 → 2H+ + Pb
2H++ 2Ag → 2Ag+ + H2
2Ag++ Pb → Pb+ + 2Ag
22279.Given Eo
Fe3+/Fe = –0.036 V, Eo
Fe2+/Fe = –0.439 V.
Fe3+/Fe = –0.036 V, Eo
Fe2+/Fe = –0.439 V.
The value of standard electrode potential for the change,
Fe3+(aq) + e– → Fe2+ will be
–0.072 V
0.385 V
0.770 V
–0.270 V
22281.Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 milliampere current. The time required to liberate 0.01 mol of H2 gas at the cathode is (1 Faraday = 96500 C mol–1)
9.65 × 104 s
19.3 × 104 s
28.95 × 104 s
38.6 × 104 s
22282.Given Eo
Cr3+/Cr = –0.72 V, Eo
Fe2+/Fe = –0.42,
Cr3+/Cr = –0.72 V, Eo
Fe2+/Fe = –0.42,
the potential for the cell Cr / Cr3+ (0.1 M) || Fe2+ (0.01 M) | Fe is
–0.26 V
0.26 V
0.339 V
–0.339 V
22283.
Calculate Λ∞
HoAc using appropriate molar conductances of the electrolytes listed above at infinite dilution in H2O at 25°C
| Electrolyte | KCl | KNO3 | HCl | NaOAc | NaCl |
| Λ∞(S cm2mol–1) | 149.9 | 145 | 426.2 | 91 | 126.5 |
Calculate Λ∞
HoAc using appropriate molar conductances of the electrolytes listed above at infinite dilution in H2O at 25°C
517.2
552.7
390.7
217.5
22284.The equivalent conductances of two strong electrolytes at infinite dilution in H2O (where ions move freely through a solution) at 25°C are given below:
Λo
CH3COONa = 91.0 S cm2 / equiv
Λo
CHCl = 426.2 S cm2 / equiv
What additional information/quantity one needs to calculate Λ° of an aqueous solution of acetic acid?
Λ° of NaCl
Λ° of CH3COOK
The limiting equivalent conductance of H+ (λo
H+)
H+)
Λ° of chloroacetic acid (ClCH2COOH)
22285.In a cell that utilizes the reaction
Zn(s) + 2H+ (aq) → Zn2+ (aq) + H2(g)
addition of H2SO4 to cathode compartment will
lower the E and shift equilibrium to the left
lower the E and shift the equilibrium to the right
increase the E and shift the equilibrium to the right
increase the E and shift the equilibrium to the left
22286.For the reduction of silver ions with copper metal the standard cell potential was found to be +0.46 V at 25°C. The value of standard Gibbs energy, ΔG° will be (F = 96500 C mol–1)
–44.5 kJ
–98.0 kJ
–89.0 kJ
–89.0 J
22287.In the electrolysis of acidulated water, it is desired to obtain 1.12 cc of hydrogen per second under S.T.P. conditions. The current to be passed is
0.965 Amp
19.3 Amp
9.65 Amp
1.93 Amp
22288.The one which decreases with dilution is
conductance
specific conductance
equivalent conductance
molar conductance
22289.Which of the following electrolytic solutions has the least specific conductance?
0.02 N
0.2 N
2 N
0.002 N
22290.The standard electrode potential for the half cell reactions are
Zn++ + 2e– → Zn, E° = – 0.76 V
Fe++ + 2e– → Fe, E° = – 0.44 V
The e.m.f. of the cell reaction Fe++ + Zn → Zn++ + Fe is
–1.20 V
+1.20 V
+0.32 V
–0.32 V
22291.Which of the following is a redox reaction?
Mg(OH)2 + 2NH4Cl → MgCl2 + 2NH4OH
CaC2O4 + 2HCl → CaCl2 + H2C2O4
NaCl + KNO3 → NaNO3 + KCl
Zn + 2AgCN → 2Ag + Zn (CN)2
22292.Given
(i) Cu2+ + 2e– → Cu, E° = 0.337 V
(ii) Cu2+ + e– → Cu+, E° = 0.153 V
Electrode potential E° for the reaction Cu+ + e– → Cu will be
0.90 V
0.30 V
0.38 V
0.52 V
22293.One faraday of electricity is passed separately through one litre of one molar aqueous solution of (i) AgNO3, (ii) SnCl4 and (iii) CuSO4. The number of moles of Ag, Sn and Cu deposited at cathode are respectively
1.0, 0.25, 0.5
1.0, 0.5, 0.25
0.5, 1.0, 0.25
0.25, 0.5, 1.0
22294.Standard free energies of formation (in kJ/mol) at 298 K are –237.2, –394.4 and –8.2 for H2O(l), CO2(g) and pentane(g), respectively. The value of Eo
cell for the pentane–oxygen fuel cell is
cell for the pentane–oxygen fuel cell is
2.0968 V
1.0968 V
0.0968 V
1.968 V
22295.The standard reduction potentials of Zn2+ | Zn, Cu2+ | Cu and Ag+ | Ag are respectively –0.76, 0.34 and 0.8V. The following cells were constructed.
a) Zn | Zn2+ || Cu2+ | Cu
b) Zn | Zn2+ || Ag+ | Ag
c) Cu | Cu2+ || Ag+ | Ag
What is the correct order Eo
cell of these cells?
b > c > a
b > a > c
a > b > c
c > a > b
22296.The standard electrode potential is measured by ______.
Electrometer
Voltmeter
Pyrometer
Galvanometer
22297.Corrosion of iron is essentially an electrochemical phenomenon where the cell reaction are ______.
Fe is oxidised to Fe2+ and dissolved oxygen in water is reduced to OH–
Fe is oxidised to Fe3+ and H2O is reduced to O2–
2
2
Fe is oxidised to Fe2+ and H2O is reduced to O–
2
2
Fe is oxidised to Fe2+ and H2O is reduced to O2