Electrochemistry MCQs Class 12: Electrochemistry is one of the most important and scoring chapters in Class 12 Chemistry for CBSE Board Exams as well as competitive exams like NEET and JEE. This chapter covers essential topics such as galvanic cells, electrolysis, Nernst equation, conductance, Faraday’s laws of electrolysis, electrochemical series, corrosion, and standard electrode potential. Every year, several MCQs and numerical-based questions are asked from this chapter.
To help students strengthen their preparation, we have provided 50 carefully selected Electrochemistry MCQs with answers. These questions cover conceptual understanding, formula-based problems, and exam-oriented practice. Practice these multiple-choice questions to improve accuracy, boost confidence, and score higher in board and entrance examinations.
Electrochemistry MCQs Class 12
1. The unit of conductivity (κ) is:
A. Ω cm
B. S cm⁻¹
C. Ω⁻¹ cm
D. Both B and C
Answer: D
2. Specific conductance decreases with:
A. Increase in dilution
B. Decrease in dilution
C. Increase in temperature
D. None
Answer: A
3. Molar conductivity increases with:
A. Increase in concentration
B. Decrease in dilution
C. Increase in dilution
D. Decrease in temperature
Answer: C
4. Unit of molar conductivity is:
A. S cm² mol⁻¹
B. Ω cm
C. S cm⁻¹
D. Ω cm²
Answer: A
5. Faraday constant is approximately:
A. 96500 C mol⁻¹
B. 965 C mol⁻¹
C. 9650 C mol⁻¹
D. 9.65 C mol⁻¹
Answer: A
6. The relation between ΔG° and E°cell is:
A. ΔG° = nFE°cell
B. ΔG° = −nFE°cell
C. ΔG° = FE°cell
D. ΔG° = −FE°cell
Answer: B
7. A galvanic cell converts:
A. Electrical energy to chemical energy
B. Chemical energy to electrical energy
C. Heat energy to chemical energy
D. Solar energy to electrical energy
Answer: B
8. In a Daniell cell, oxidation occurs at:
A. Cathode
B. Salt bridge
C. Anode
D. Electrolyte
Answer: C
9. Reduction occurs at:
A. Anode
B. Cathode
C. Electrolyte
D. Salt bridge
Answer: B
10. The standard electrode potential of hydrogen electrode is:
A. 1 V
B. 0 V
C. −1 V
D. 0.5 V
Answer: B
11. The Nernst equation at 298 K is:
A. E = E° − (0.0591/n) log Q
B. E = E° + (0.0591/n) log Q
C. E = 0.0591 log Q
D. E = nF log Q
Answer: A
12. Conductivity increases with:
A. Increase in temperature
B. Decrease in temperature
C. Increase in pressure
D. None
Answer: A
13. Kohlrausch’s law is applicable to:
A. Strong electrolytes at high concentration
B. Weak electrolytes at infinite dilution
C. Nonelectrolytes
D. Gases
Answer: B
14. Corrosion is:
A. Reduction process
B. Oxidation process
C. Neutral process
D. Electrolysis
Answer: B
15. Rusting of iron requires:
A. Only oxygen
B. Only water
C. Both oxygen and water
D. Nitrogen
Answer: C
16. EMF of cell is:
A. Sum of electrode potentials
B. Difference of electrode potentials
C. Product of potentials
D. None
Answer: B
17. If E°cell is positive, the reaction is:
A. Non-spontaneous
B. Spontaneous
C. Neutral
D. Reversible
Answer: B
18. Electrolysis involves:
A. Spontaneous reaction
B. Non-spontaneous reaction
C. No reaction
D. Neutral reaction
Answer: B
19. Unit of resistivity is:
A. Ω cm
B. S cm
C. Ω⁻¹ cm
D. S cm⁻¹
Answer: A
20. Conductance is reciprocal of:
A. Resistivity
B. Resistance
C. Voltage
D. Current
Answer: B
21. Specific conductivity (κ) depends on:
A. Nature of electrolyte
B. Number of ions per unit volume
C. Temperature
D. All of the above
Answer: D
22. On increasing dilution, the molar conductivity of a weak electrolyte:
A. Decreases
B. Remains constant
C. Increases sharply
D. Becomes zero
Answer: C
23. The unit of cell constant is:
A. cm
B. cm⁻¹
C. Ω cm
D. S cm⁻¹
Answer: B
24. The value of 0.0591 in the Nernst equation is valid at:
A. 273 K
B. 298 K
C. 310 K
D. 300 K
Answer: B
25. The number of electrons transferred in Zn²⁺ + 2e⁻ → Zn is:
A. 1
B. 2
C. 3
D. 4
Answer: B
26. In a galvanic cell, electrons flow from:
A. Cathode to anode
B. Anode to cathode
C. Salt bridge to cathode
D. Cathode to salt bridge
Answer: B
27. The EMF of a cell becomes zero when:
A. Reaction starts
B. Reaction is spontaneous
C. Reaction reaches equilibrium
D. Temperature increases
Answer: C
28. According to Kohlrausch’s law, at infinite dilution:
A. Molar conductivity is minimum
B. Molar conductivity is maximum
C. Conductivity is zero
D. Resistance is zero
Answer: B
29. The charge required to deposit 1 mole of Ag is:
A. 1 F
B. 2 F
C. 3 F
D. 0.5 F
Answer: A
30. In electrolysis of molten NaCl, sodium is obtained at:
A. Anode
B. Cathode
C. Salt bridge
D. Electrolyte
Answer: B
31. The oxidation number of iron in rust (Fe₂O₃) is:
A. +2
B. +3
C. +1
D. 0
Answer: B
32. If E°cell is negative, the reaction is:
A. Spontaneous
B. Non-spontaneous
C. Neutral
D. Exothermic
Answer: B
33. The relation between equilibrium constant (K) and E°cell is:
A. E° = (0.0591/n) log K
B. E° = −(0.0591/n) log K
C. E° = nF log K
D. E° = log K
Answer: A
34. Conductivity cell is used to measure:
A. Voltage
B. Current
C. Resistance of solution
D. Temperature
Answer: C
35. The process of coating iron with zinc is called:
A. Electroplating
B. Galvanization
C. Alloying
D. Tinning
Answer: B
36. During electrolysis of water, oxygen is liberated at:
A. Cathode
B. Anode
C. Both electrodes
D. Salt bridge
Answer: B
37. The strongest reducing agent has:
A. Highest positive E° value
B. Lowest (most negative) E° value
C. Zero E° value
D. Moderate E° value
Answer: B
38. The strongest oxidizing agent has:
A. Highest positive E° value
B. Lowest E° value
C. Zero potential
D. Negative potential
Answer: A
39. In a Daniell cell, the electrolyte used in salt bridge is generally:
A. KCl
B. NaCl
C. HCl
D. NaOH
Answer: A
40. Resistance of a conductor is directly proportional to:
A. Area
B. Length
C. Temperature only
D. Conductivity
Answer: B
41. Resistance of a conductor is inversely proportional to:
A. Length
B. Area
C. Temperature
D. Resistivity
Answer: B
42. The SI unit of EMF is:
A. Ampere
B. Coulomb
C. Volt
D. Ohm
Answer: C
43. One Faraday is equal to:
A. Charge of 1 mole of electrons
B. Charge of 2 moles of electrons
C. 1 Coulomb
D. 1000 Coulomb
Answer: A
44. In electrolysis, oxidation occurs at:
A. Cathode
B. Anode
C. Salt bridge
D. Electrolyte
Answer: B
45. In galvanic cell, cathode is:
A. Negative electrode
B. Positive electrode
C. Neutral electrode
D. Inactive electrode
Answer: B
46. The cell reaction stops when:
A. EMF increases
B. Concentration increases
C. EMF becomes zero
D. Temperature decreases
Answer: C
47. Electrochemical series is arranged according to:
A. Oxidation potential
B. Reduction potential
C. Atomic mass
D. Density
Answer: B
48. Higher the concentration of ions, higher the:
A. Resistance
B. Conductivity
C. Resistivity
D. EMF
Answer: B
49. In a concentration cell, EMF arises due to:
A. Temperature difference
B. Pressure difference
C. Concentration difference
D. Volume difference
Answer: C
50. Corrosion of iron is faster in:
A. Dry air
B. Moist air
C. Pure nitrogen
D. Vacuum
Answer: B