Electrochemistry  MCQs

MCQs of Electrochemistry

Showing 131 to 140 out of 158 Questions
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131.
Standard electrode potential are E°Fe2+ | Fe = -0.49 V, E°Fe3+ | Fe2+ =0.77 V and Fe all the three are combined, _____ .
(a) Fe3+ will increase
(b) Fe3+ will decrease
(c) Fe2+ or Fe3+ will not change
(d) Fe2+ will decrease
Answer:

Option (b)

132.
Based on the following information state the strongest oxidant.

(i) [Fe(CN)6]4- → [Fe(CN)6]3- + e- ; E° = -0.35 V

(ii) Fe2+ → Fe3+ + e- ; E° = -0.77 V

(a) Fe3+
(b) [Fe(CN)6]3-
(c) [Fe(CN)6]4-
(d) Fe2+
Answer:

Option (a)

133.
Al2O3 gets reduced at low potential and high electric current. If 4 × 104 A electric current is passed for 6 hours through molten Al2O3, what will be the mass of Al liberated ? ( Efficiency of electric current = 100%, Atomic weight of Al = 27 g/mole)
(a) 2.4 × 105 g
(b) 1.3 × 104 g
(c) 9.0 × 103 g
(d) 8.1 × 104 g
Answer:

Option (d)

134.
How long should 9.65 A electric current be passed to get 1 millimole Al metal from Al3+ solution ?
(a) 30 seconds
(b) 10 seconds
(c) 30,000 seconds
(d) 1000 seconds
Answer:

Option (a)

135.
Volume of O2 liberated during electrolysis of water is 2.24 dm3. What should be the volume of H2 under the same condition ?
(a) 2.24 dm3
(b) 1.12 dm3
(c) 4.48 dm3
(d) 2.56 dm3
Answer:

Option (c)

136.
Calculate the equilibrium constant of the reaction.

Cus + 2Agaq+ ⇄ Cuaq2+ + 2Ags ; E°cell = 0.46 V

(a) Kc = 3.83 × 1020
(b) Kc = 5.92 × 1010
(c) Kc = 1.92 × 105
(d) Kc = 3.92 × 1015
Answer:

Option (d)

137.
Calculate the equilibrium constant for the cell reaction given below at 298 K temperature.

Cu(s) + 2Ag+(aq) → Cu2+(aq) + 2Ag(s) ; E°cell = 0.46 V

(a) 2.0 × 1010
(b) 4.0 × 1010
(c) 4 × 1015
(d) 2.4 × 1010
Answer:

Option (c)

138.
Which of the following statement (s) differentiate between electrochemical and electrolytic cell ?

(a) Oxidation-Reduction reactions occurring at the electrodes.

(b) Spontaneous or non-spontaneous nature of the chemical process.

(c) Positive and negative nature of anode.

(d) Use of salt bridge.

(e) Flow of reactions.

(f) Number of electrodes used.

(a) (d), (a), (c), (e)
(b) (b), (a), (c)
(c) (b), (d), (c)
(d) (a), (b), (d), (f)
Answer:

Option (c)

139.
The values of standard oxidation potential of Sn, Zn and Mg is 0.14 V, 0.76 V and 2.37 V respectively. Arrange their strength as oxidizing agent.
(a) Sn >Zn > Mg
(b) Mg < Sn < Zn
(c) Zn > Sn > Mg
(d) Mg > Zn > Sn
Answer:

Option (a)

140.
3.48 g Cu is produced on cathode when 10 A current is passed for 193 minutes through CuSO4 solution at 300 K temperature and 1 bar pressure. What is the efficiency of the electrolytic cell ? What is the volume of O2 in litres released at anode ? ( Cu = 63.5, F = 96,500 C)
(a) Efficiency = 80%, 5.986 L O2 gas
(b) Efficiency = 85%, 5.986 L O2 gas
(c) Efficiency = 90%, 9.586 L O2 gas
(d) Efficiency = 95%, 15.96 L O2 gas
Answer:

Option (a)

Showing 131 to 140 out of 158 Questions
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