MCQ Electrochemistry Class-12 ISC Chapter-3 Chemistry Question Objective Type

(a) 1 F

(b) 3 F

(c) 5 F

(d) 6 F

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 3 F [/su_spoiler]

Question 2: If 96500 coulomb electricity is passed through CuSO₄ solution, it will liberate

(a) 63.5 gm of Cu

(b) 31.76 gm of Cu

(c) 96500 gm of Cu

(d) 100 gm of Cu

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 31.76 gm of Cu [/su_spoiler]

Question 3: A new galvanic cell of E^u more than E°dl of Daniel cell is connected to Daniel cell in a manner that new cell gives electrons to cathode, what will happen

(a) E_cell will increase

(b) E_cell will decrease

(c) No change will take place

(d) Daniel cell will work as electrolytic cell where Zn will be deposite on zinc rod and copper will dissolve from copper rod.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) Daniel cell will work as electrolytic cell where Zn will be deposite on zinc rod and copper will dissolve from copper rod. of Cu [/su_spoiler]

Question 4: Standard solution of KNO₃ is used to make a salt bridge because

(a) Velocity of K+ is greater than that of NO−3.

(b) Velocity of NO−3 is greater than that of K⁺.

(c) Velocity of both K⁺ and NO−3 are nearly same

(d) KNO₃ is highly soluble in water.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Velocity of both K⁺ and NO−3 are nearly same
[/su_spoiler]

Question 5: For the electro-chemical cell:

M| M+|| X^–| X, E0𝑀+,𝑀 = 0.44 V and E0𝑥,𝑥− = 0.33 V
From the data one can deduce that

(a) M+ X → M⁺ + X^– is the spontaneous change

(b) M⁺ + X^– → M + X is the spontaneous reaction

(c) E_cell = 0.77 V

(d) E_cell = -0.77 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) M⁺ + X^– → M + X is the spontaneous reaction
[/su_spoiler]

Question 6: Galvanised iron sheets are coated with

(a) Carbon

(b) Copper

(c) Zinc

(d) Nickel

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Zinc

[/su_spoiler]

Question 7: How many coulombs are required for the oxidation of 1 mole of H₂O to O₂?

(a) 1.93 × 10⁵ C

(b) 9.65 × 10⁴ C

(c) 3.86 × 10⁵ C

(d) 4.825 × 10⁵ C

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 1.93 × 10⁵ C
[/su_spoiler]

Question 8: Rust is a mixture of

(a) FeO and Fe (OH)₃

(b) FeO and Fe (OH)₂

(c) Fe₂O₃ and Fe (OH)₃

(d) Fe₃O₄ and Fe (OH)₃

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Fe₂O₃ and Fe (OH)₃ [/su_spoiler]

Question 9:  If limiting molar conductivity of Ca²⁺ and Cl^– are 119.0 and 76.3 S cm² mol^-1, then the value of limiting molar conductivity of CaCl2 will be

(a) 195.3 S cm² mol^-1

(b) 271.6 S cm² mol^-1

(c) 43.3 S cm² mol^-1

(d) 314.3 S cm² mol^-1.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 271.6 S cm² mol^-1 [/su_spoiler]

Question 10: Fused NaCl on electrolysis gives ………….. on cathode.

(a) Chlroine

(b) Sodium

(c) Sodium amalgam

(d) Hydrogen

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) Sodium [/su_spoiler]

Question 11: Ag⁺(aq) + e^– → Ag(s) E° = + 0.80 V

Fe²⁺(aq)+ + 2e^– → Fe(s) E° = – 0.44 V

What is emf of
Fe(s) + 2Ag⁺(aq) → Fe²⁺(aq) + 2Ag(s)

(a) 1.16 V

(b) 1.24 V

(c) 2.04 V

(d) -1.16 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 1.24 V
[/su_spoiler]

Question 12: A conductivity cell containing electrodes made up of

(a) Gold

(b) Silver

(c) Platinised platinum

(d) Copper

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Platinised platinum [/su_spoiler]

Question 13: The Standard electrode potentials for the half cell reactions are as follows

Zn ? Zn²⁺ + 2e^– [E° = 0.41 V]
Fe ? Fe²⁺ + 2e^– [E° = 0.76 V]

(a) -0.35 V

(b) 0.35 V

(c) + 1.17 V

(d) -1.17 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 0.35 V
[/su_spoiler]

Question 14: Standard electrode potential data are useful for understanding the suitability of an oxidant in a redox titration. Some half cell reactions and their standard potentials are given below:

MNO^–₄ (aq) + 8H⁺ (aq) + 5e^– → Mn²⁺ (aq) + 4H₂O (1) E° = 1.51 V
Cr₂O₇^2- (aq) + 14H⁺ (aq) + 6e^– → 2 Cr³⁺ (aq) + 7H₂O (1) E° = 1.38 V
Fe^3+- (aq) + e^– ? Fe²⁺ (aq) E° = 0.77 V
Cl₂ (g) + 2e^– ? 2Cl^– (aq) E° = 1.40 V

Identify the only incorrect statement regarding the quantitative estimation of aqueous Fe (NO₃)₂.

(a) MnO−4 can be used in aqueous HCl.

(b) Cr₂O2−7 can be used in aqueous HCl.

(c) MnO−4 can be used in aqueous H₂SO₄.

(d) Cr₂O2−7 can be used in aqueous H₂SO₄.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) MnO−4 can be used in aqueous HCl.
[/su_spoiler]

Question 15: The standard reduction potentials of Cu²⁺/Cu and Cu²⁺/Cu⁺ are 0.337 and 0.153 respectively. The standard electrode potential of Cu⁺/Cu half cell is

(a) 0.184 V

(b) 0.827 V

(c) 0.521V

(d) 0.490 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 0.521V
[/su_spoiler]

Question 16: The standard reduction potentials of X, Y, Z metals are 0.52, -3.03, -1.18 respectively. The order of reducing power of the corresponding metals is:

(a) Y > Z > X

(b) X > Y > Z

(c) Z > Y > X

(d) Z > X > Y

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) Y > Z > X
[/su_spoiler]

Question 17: Which of the following is not a good conductor?

(a) Cu

(b) NaCl (aq)

(c) NaCl (molten)

(d) NaCl(s)

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) NaCl(s) [/su_spoiler]

Question 18: The reaction, 3ClO^– (aq) → ClO₃ (aq) + 2Cl^– (aq) is an example of

(a) Oxidation reaction

(b) Reduction reaction

(c) Disproportionation reaction

(d) Decomposition reaction

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Disproportionation reaction
[/su_spoiler]

Question 19: The emf of the cell:

Ni / Ni²⁺ (1.0 M) // Au³⁺ (1.0 M) / Au (E° = -0.25 V for Ni²⁺/Ni; E° = 1.5 V for Au³⁺/Au) is

(a) 1.25 V

(b) -1.25 V

(c) 1.75 V

(d) 2.0 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 1.75 V [/su_spoiler]

Question 20: The standard electrode potentials for the half cell reactions are:

Zn → Zn^2-– 2e^– E° = 0.76 V
Fe → Fe^2- + 2^– E° = -0.41 V
The emf of the cell reaction
Fe^2- + Zn → Zn^2- + Fe is

(a) -0.35 V

(b) +0.35 V

(c) -1.17 V

(d) +1.17 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) +0.35 V
[/su_spoiler]

Question 21: Which of the following is a secondary cell?

(a) Leclanche cell

(b) Lead storage battery

(c) Concentration cell

(d) All of these

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) Lead storage battery [/su_spoiler]

Question 22: Which of the following statement is correct?

(a) E_Cell and ∆_rG of cell reaction both are extensive properties.

(b) E_Cell and ∆_rG of cell reaction both are . intensive properties.

(c) E_Cell is an intensive property while ∆_rG of cell reaction is an extensive property.

(d) E_Cell is an extensive property while ∆_rG of cell reaction is an intensive property.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) E_Cell is an intensive property while ∆_rG of cell reaction is an extensive property.
[/su_spoiler]

Question 23: The e.m.f. of the cell Zn/Zn²⁺ (0.01 M) || Fe²⁺ (0.001 M) Fe at 298 K is 0.2905 volt. Then the value of equilibrium constant for the cell reaction is:

(a) e^0.32/0.0295

(b) 10^0.32/0.0295

(c) 10^0.26/0.0295

(d) 10^0.32/0.0591

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 10^0.32/0.0295 [/su_spoiler]

Question 24: If E°_Fe²⁺/Fe = -0.441 V and E°_{Fe²⁺/Fe²⁺} = 0.771 V, the standard EMF of the reaction,

Fe + 2Fe³⁺ → 3Fe²⁺ will be

(a) 1.212 V

(b) 0.111 V

(C) 0.330 V

(d) 1.653 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 1.212 V  [/su_spoiler]

Question 25:  For a certain redox reaction, E° is positive. This means that

(a) ΔG° is positive, K is greater than 1

(b) ΔG° is positive, K is less than 1

(c) ΔG° is negative, K is greater than 1

(d) ΔG° is negative, K is less than 1

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) ΔG° is negative, K is greater than 1
 [/su_spoiler]

Question 26: Cell reaction is spontaneous, when

(a) E0𝑟𝑒𝑑 is negative

(b) ΔG° is negative

(c) E0𝑜𝑥𝑖𝑑 is Positive

(d) ΔG° is positive

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) ΔG° is negative [/su_spoiler]

Question 27:  While charging the lead storage battery _________ . [NCERT Exemplar]

(a) PbSO₄ anode is reduced to Pb.

(b) PbSO₄ cathode is reduced to Pb.

(c) PbSO₄ cathode is oxidised to Pb.

(d) PbSO₄ anode is oxidised to PbO₂.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) PbSO₄ anode is reduced to Pb. [/su_spoiler]

Question 28: Λ of M/32 solution of weak acid is 8 S cm2 mol^-1 and limiting molar conductivity is 400 S cm2 mol1. Ka for acid is

(a) 1.25 × 10^-6

(b) 6.25× 10^-4

(c) 1.25 × 10^-4

(d) 1.25 × 10^-5

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) 1.25 × 10^-5 [/su_spoiler]

Question 29: The positive value of the standard electrode potential of Cu²⁺/Cu indicates that _________

(a) this redox couple is a stronger reducing agent than the H⁺/H₂ couple.

(b) this redox couple is a stronger oxidising agent than H⁺/H₂.

(c) Cu can displace H₂ from acid.

(id) Cu cannot displace H₂ from acid.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) this redox couple is a stronger oxidising agent than H⁺/H₂. [/su_spoiler]

Question 30:  The charge required for the reduction of 1 mol of MnO₂^– to MnO₂ is

(a) 1 F

(b) 3 F

(c) 5 F

(d) 6 F

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 1 F  [/su_spoiler]

Question 31: The volume of H₂ gas at NTP obtained by passing 4 amperes through acidified H₊O for 30 minutes is:

(a) 0.0836 L

(b) 0.0432 L

(c) 0.1672 L

(d) 0.836 L

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 0.0836 L
[/su_spoiler]

Question 32:4.5 g of aluminium (at. mass 27 amu) is deposited at cathode from Al³⁺ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H+ ions in solution by the same quantity of electric charge will be:

(a) 44.8 L

(b) 11.2 L

(c) 22.4 L

(d) 5.6 L

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 44.8 L
[/su_spoiler]

Question 33:For a spontaneous reaction, ?G, equilibrium constant K and E0𝑐𝑒𝑙𝑙 will be respectively.

(a) – ve > 1, + ve

(b) + ve > 1 – ve

(c) -ve, < 1, -ve

(d) -ve, > 1, -ve

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) – ve > 1, + ve
[/su_spoiler]

Question 34:The amount of electricity required to deposit 1 mol of aluminium from a solution of AlCl₃ will be

(a) 0.33 F

(b) 1 F

(c) 3 F

(d) 1 ampere

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 3 F [/su_spoiler]

Question 35: The reaction, 3ClO^– (aq) → ClO₃ (aq) + 2Cl^– (aq) is an example of

(a) Oxidation reaction

(b) Reduction reaction

(c) Disproportionation reaction

(d) Decomposition reaction

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Disproportionation reaction
[/su_spoiler]

Question 36: The emf of the cell:

Ni / Ni²⁺ (1.0 M) // Au³⁺ (1.0 M) / Au (E° = -0.25 V for Ni²⁺/Ni; E° = 1.5 V for Au³⁺/Au) is

(a) 1.25 V

(b) -1.25 V

(c) 1.75 V

(d) 2.0 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 1.75 V
[/su_spoiler]

Question 37: The standard emf of a galvanic cell involving cell reaction with n = 2 is formed to be 0.295 V at 25° C. The equilibrium constant of the reaction would be

(a) 1.0 × 10¹⁰

(b) 2.0 × 10¹¹

(c) 4.0 × 10¹²

(d) 1.0 × 10²

[Given F = 96500 (mol^-1); R = 8.314 JK^-1 mol^-1]

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 1.0 × 10¹⁰
[/su_spoiler]

Question 38: If E°_Fe²⁺/Fe = -0.441 V and E°_{Fe²⁺/Fe²⁺} = 0.771 V, the standard EMF of the reaction,
Fe + 2Fe³⁺ → 3Fe²⁺ will be

(a) 1.212 V

(b) 0.111 V

(C) 0.330 V

(d) 1.653 V

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(a) 1.212 V [/su_spoiler]

Question 39: The charge required for reducing 1 mole of MnO−4 to Mn^2- is

(a) 1.93 × 10⁵ C

(b) 2.895 × 10⁵ C

(c) 4.28 × 10⁵ C

(d) 4.825 × 10⁵ C

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) 4.825 × 10⁵ C [/su_spoiler]

Question 40: How much electricity in in terms of Faraday is required to produce 100 g of Ca from molten CaCl₂?

(a) 1F

(b) 2F

(c) 3F

(d) 5F

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) 5F [/su_spoiler]

Question 41:  If a current of 1.5 ampere flows through a metallic wire for 3 hours, then how many electrons would flow through the wire?

(a) 2.25 × 10²² electrons

(b) 1.13 × 10²³ electrons

(c) 1.01 × 10²³ electrons

(d) 4.5 × 10²³ electrons

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 1.01 × 10²³ electrons
[/su_spoiler]

Question 42:  How many coulombs of electricity is required to reduce 1 mole of Cr₂O2−7 in acidic medium?

(a) 4 × 96500 C

(b) 6 × 96500 C

(c) 2 × 96500 C

(d) 1 × 96500 C

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 6 × 96500 C
[/su_spoiler]

Question 43: A current of 1.40 ampere is passed through 500 mL of 0.180 M solution of zinc sulphate for 200 seconds. What will be the molarity of Zn²⁺ions after deposition of zinc?

(a) 0.154 M

(b) 0.177 M

(c) 2 M

(d) 0.180 M

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 0.177 M [/su_spoiler]

Question 44: For a cell reaction involving two electron change the standard emf of the cell is found to be 0.295 V at 25°C. The equilibrium constant for the reaction at 25°C will be:

(a) 2.95 × 10²

(b) 10

(c) 1 × 10¹⁰

(d) 1 × 10^-10

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 1 × 10¹⁰
[/su_spoiler]

Question 45: If Zn²⁺/Zn electrode is diluted 100 times, then the change in emf is

(a) increase of 59 mV

(b) decrease of 59 mV

(c) increase of 29.5 mV

(d) decrease of 29.5 mV.

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) decrease of 59 mV
[/su_spoiler]

Question 46:. If the equivalent conductance of 1 M benzoic acid is 12.8 ohm^-1 cm² and if the conductance of benzoate ion and H⁺ ion are 42 and 288.42 ohm^-1 cm² respectively, its degree of dissociation is:

(a) 39%

(b) 3.9%

(c) 0.35%

(d) 0.039%

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) 3.9%
[/su_spoiler]

Question 47:. The half-cell reactions for rusting of iron are

2H⁺ + 12 O₂ + 2𝑒¯ ? H₂O, E° = + 1.23 V
Fe²⁺ + 2𝑒¯ ? Fe (s), E° = – 0.44 V
?G° (in kj) for the reaction is

(a) -76

(b) -322

(c) -122

(d) -176

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(b) -322
[/su_spoiler]

Question 48:. An aqueous solution containing one mole per litre of each of Cu(NO₃)₂, AgNO₃, Hg (NO₃)₂ and Mg (NO₃)₂ is being electrolysed using inert electrodes. The values of standard electrode (reduction) potentials in volts are Ag/Ag⁺ = + 0.80, Hg/ Hg²⁺ = 0.79, Cu/Cu²⁺ = 0.34, Mg/Mg²⁺ = -2.37.
With increasing voltage, the sequence of deposition of metals on cathode will be

(a) Ag, Hg, Cu, Mg

(b) Mg, Cu, Hg, Ag

(c) Ag, Hg, Cu

(d) Cu, Hg, Ag

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) Ag, Hg, Cu [/su_spoiler]

Question 49: How much time is required to deposit 1 × 10^-3 cm thick layer of silver (density of 1.05 g cm^-3) on a surface of area 100 cm² by passing a current of 5 A through AgNO₃ solution?

(a) 125 s

(b) 115 s

(c) 18.7 s

(d) 27.25 s

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(c) 18.7 s [/su_spoiler]

Question 50: The highest electrical conductivity of the following aqueous solutions is of?

(a) 0.1 M acetic acid

(b) 0.1 M chloro acetic acid

(c) 0.1 M fluoroacetic acid

(d) 0.1 M difluoro acetic acid

[su_spoiler title=”Answer” style=”fancy” icon=”caret”]Correct Answer :(d) 0.1 M difluoro acetic acid [/su_spoiler]

-: End of MCQ Electrochemistry Class-12 ISC Chapter-3 Objective Type Question :-