ELECTROCHEMISTRY MCQs

By: Prof. Dr. Fazal Rehman | Last updated: May 23, 2025

1. : Which relation corresponds to Faraday’s law of electrolysis?
(A) ΔF = -nFE°
(B) E = mc²
(C) E = hυ
(D) m = Zt

2. : Which statement is not true with reference to cell constant?
(A) The dimensions of cell constant is cm
(B) Specific conductance does not vary with concentration
(C) It is measured with KCl solution
(D) It is helpful and used to determine the specific conductance

3. : Which solid is a better conductor of electricity?
(A) Pure NaCl crystals
(B) Sulfur
(C) Diamond
(D) Graphite

4. : ____ is the device that converts the energy of fuel directly into electrical energy.
(A) Galvanic cell
(B) Electrolytic cell
(C) Concentration cell
(D) Fuel cell

5. : When some quantity of electricity is passed through two electrolytic cells, the ratio of the mass of the products obtained at the cathode is the same as the ratio of their
(A) Equivalent masses
(B) Atomic masses
(C) Densities
(D) Atomic numbers

6. : The blue color of CuSO₄ disappears on adding Zn granules to it. It is because of
(A) Oxidation of Cu atom
(B) Oxidation of Zn²⁺
(C) Reduction of Zn²⁺
(D) Reduction of Cu²⁺

7. : Which statement is not true with reference to ionic conductors?
(A) Ionic conductance is due to movement of the ions
(B) It decreases with rise in temperature
(C) It involves oxidation-reduction reaction
(D) It involves the flow of matter

8. : The unit of specific conductance will be
(A) Mho cm
(B) Ohm cm
(C) Ohm cm⁻¹
(D) S cm⁻¹

9. : The conductance of 1 cm³ of an electrolyte solution is called its
(A) Specific resistance
(B) Molar conductance
(C) Specific conductance
(D) Equivalent conductance

10. : Which ion has high mobility in aqueous solution?
(A) K⁺
(B) Al³⁺
(C) Ca²⁺
(D) H⁺

11. : Which solution of NaCl will have the highest specific conductance?
(A) 0.001 N
(B) 0.01 N
(C) 1.0 N
(D) 0.1 N

12. : Electrolytic conduction is due to the movement of which of the following?
(A) Electrons
(B) Molecules
(C) Atoms
(D) Ions

13. : Which statement is not true with reference to Arrhenius theory of electrolytic dissociation?
(A) Electrolytes dissociate into charged species called ions in aqueous solution
(B) The ions are not free to move
(C) The extent of dissociation also depends on the temperature of the electrolyte
(D) The extent of dissociation depends on the concentration of the electrolyte

14. : The branch of chemistry which is concerned with the interrelation of electrical and chemical energy is called
(A) Reaction dynamics
(B) Electrochemistry
(C) Surface chemistry
(D) Kinetics

15. : Equivalent conductance is expressed in the units
(A) S cm² eq⁻¹
(B) S cm eq⁻¹
(C) S cm² eq⁻¹
(D) S cm⁻¹ eq⁻¹

16. : The fraction of the total current carried by an ion is called its
(A) Transport number
(B) Ionic mobility
(C) Limiting ionic conductance
(D) None of A, B, and C

17. : If for a solution of an electrolyte, t⁺ is the transport number of the cation, then the transport number of the anion will be
(A) t⁺/2
(B) 1 + t⁺
(C) 1 – t⁺
(D) (1 – t)/2

18. : Which process forever involves an increase in oxidation number?
(A) Oxidation
(B) Decomposition
(C) Reduction
(D) Hydrolysis

19. : Which statement is true?
(A) The transport number of a cation is equal to its equivalent conductance
(B) The transport number of an ion is inversely proportional to its mobility
(C) The sum of the transport numbers of all the ions present in a solution is unity
(D) The transport number of a cation is equal to that of the anion

20. : In which compound is the oxidation number of Cl +3?
(A) ClF₃
(B) ClO₃
(C) ICl
(D) HClO₄

21. : What happens during a reaction of copper with aqueous solution of silver nitrate?
(A) Silver atoms are reduced
(B) Cu ions are reduced
(C) Nitrate ions are reduced
(D) Silver ions are reduced

22. : What is the unit for the cell constant?
(A) Ώ⁻¹ cm⁻¹
(B) cm²
(C) cm⁻¹
(D) cm⁻³

23. : During the titration of weak acid against NaOH, the conductance of the solution after the neutralization point
(A) Is constant
(B) Increases
(C) Varies irregularly
(D) Decreases

24. : According to the Debye-Huckel theory of strong electrolytes, an ion moving in an atmosphere of oppositely charged ions experiences a drag. This effect is called
(A) Concentration effect
(B) Electrophoretic effect
(C) Inter-ionic effect
(D) Asymmetric effect

25. : Which procedure permanently causes the oxidation number to decrease?
(A) Reduction
(B) Hydrolysis
(C) Oxidation
(D) Decomposition

26. : What is the oxidation number of I in HIO₄?
(A) +7
(B) +3
(C) +5
(D) +6

27. : Which reaction is not a redox reaction?
(A) Na₂O + H₂SO₄ → Na₂SO₄ + H₂O
(B) 2Na + O₂ → Na₂O₂
(C) SO₂ + 2H₂S → 2H₂O + S
(D) NO + 2H₂S → 2H₂O + N

28. : What is the oxidation number of Mn in KMnO₄?
(A) +5
(B) –7
(C) +7
(D) +3

29. : Which species is the strongest oxidizing agent in their standard state?
(A) Cl⁻
(B) Fe²⁺
(C) Cu²⁺
(D) Co³⁺

30. : Which statement is not true with respect to electrolytic conductors?
(A) New products are shown at the electrodes
(B) A single stream of electrons flow from cathode to anode
(C) Positive temperature coefficient is observed for the conductance
(D) Ions are responsible to carry current

31. : Which electrodes have E°red = 0?
(A) Cl₂/Ag⁺, Aq
(B) Cl₂/Cl⁻, Pt
(C) H₂/2H⁺, Pt
(D) Cu²⁺/Cu

32. : The species undergoing reduction in the following reaction is: Cr + 2H₂O + ClO → Cr³⁺ + 3Cl⁻ + 6OH⁻
(A) ClO
(B) H₂O
(C) Cr
(D) Cl⁻

33. : Which is a cathodic reaction?
(A) Fe²⁺ → Fe²⁺
(B) 2H₂O → 2OH⁻ + H₂
(C) 4OH⁻ → 2H₂O + O₂
(D) 2SO₄²⁻ → S₂O₈²⁻

34. : From the activity series, the ideal reducing agent among the following is
(A) I⁻ ions
(B) Cl⁻ ions
(C) Br⁻ ions
(D) F⁻ ions

35. : In the cell reaction Cu + 2Ag⁺ → Cu²⁺ + 2Ag, the reduction half reaction is
(A) Cu – 2e⁻ → Cu
(B) 2Ag + 2e⁻ → 2Ag
(C) 2Ag → 2Ag⁺ + 2e⁻
(D) Cu²⁺ + 2e⁻ → Cu

36. : The electrode Pt/Fe²⁺(C₁), Fe³⁺(C₂) belongs to the type
(A) Gas electrodes
(B) Metal-metal insoluble salt electrode
(C) Amalgam electrodes
(D) Inert metal electrodes

37. : According to the latest convention, the e.m.f. of a cell may be expressed in terms of the reduction potentials of RHS electrode (ER) and LHS electrode (EL) as
(A) Ecell = EL – ER
(B) Ecell = ER/EL
(C) Ecell = ER + EL
(D) Ecell = ER – EL

38. : Oxidation number of S in H₂SO₄ is
(A) +8
(B) +4
(C) +6
(D) +2

39. : Which statement is not true regarding galvanic cells?
(A) Oxidation occurs at the anode
(B) Ions carry current inside the cell
(C) When the e.m.f. of the cell is positive, the cell reaction is spontaneous
(D) Electrons flow around the external circuit, from cathode to anode

40. : The mathematical equation E – E° = -RT/nF ln Q, where Q is the reaction quotient, is called
(A) Nernst equation
(B) Free energy equation
(C) Helmholtz equation
(D) Newton’s equation

41. : The emf of the cell Zn|Zn²⁺ || Ag⁺|Ag is independent of
(A) Temperature
(B) The molarity of Zn ions in the solution
(C) The molarity of Ag⁺ ions in the solution
(D) The volume of Zn²⁺ and Ag⁺ solutions

42. : For which cells is the standard voltage zero?
(A) Daniel cell
(B) Fuel cell
(C) Electrolytic cell
(D) Concentration cell

43. : Cell potential depends on which of the following?
(A) Temperature
(B) Concentration of ions
(C) Nature of electrolyte
(D) All of A, B, and C

44. : The depolarizer used in dry cell batteries is
(A) NH₄Cl
(B) Na₃PO₄
(C) KOH
(D) MnO₂

45. : In a lead storage battery, the anode reaction is
(A) Pb²⁺ + 2e⁻ → Pb
(B) None of A, B, and C
(C) PbO + H₂SO₄ → PbSO₄ + H₂O
(D) Pb + H₂SO₄ → PbSO₄ + 2H⁺ + 2e⁻

46. : The cell in which a non-spontaneous redox reaction takes place as a result of electricity is known as
(A) Voltaic cell
(B) Dry cell
(C) Daniel cell
(D) Electrolytic cell

47. : The process of burning hydrogen in an environment of oxygen to form water is described as
(A) Oxidation only
(B) Reduction only
(C) Hydrogenation of oxygen
(D) Redox reaction

48. : The reaction taking place at the anode in galvanic cells is
(A) Reduction
(B) Oxidation
(C) Hydrolysis
(D) Ionization

49. : A half-cell reaction is one that
(A) Forever oxidizes
(B) Goes only half way to completion
(C) Involves a half mole of the concentration of the solution
(D) Occurs at one electrode

50. : The oxidation state of carbon in sucrose is
(A) Zero
(B) +3
(C) -4
(D) +4