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Electrochemistry CBSE Class 12 MCQ & Practice Questions

Practice Electrochemistry MCQs for CBSE Class 12 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Electrochemistry Revision Guide for CBSE Class 12 Chemistry

Electrochemistry connects chemical change with electrical energy. For exam preparation, students should be comfortable with galvanic and electrolytic cells, electrode potentials, cell notation, conductance and electrolysis. The most useful approach is to understand what each equation represents before applying it to numerical problems.

For CBSE Class 12 Chemistry, revise the sign conventions for anode and cathode, standard electrode potential, the Nernst equation, molar conductivity and Faraday laws. After concept revision, solve mixed conceptual and numerical MCQs so that formula selection becomes automatic under time pressure.

Important Topics

  • Electrochemical and galvanic cells
  • Standard electrode potential and cell EMF
  • Nernst equation and reaction quotient
  • Conductance, conductivity and molar conductivity
  • Kohlrausch law and limiting molar conductivity
  • Electrolysis and Faraday laws

Important Formulae & Relationships

  • Ecell = Ecathode − Eanode
  • E = E° − (RT/nF) ln Q
  • At 298 K: E = E° − (0.0591/n) log Q
  • Λm = κ × 1000 / C
  • m = (MIt)/(nF)

Use formulas only after checking the required units, sign convention and assumptions for the question.

What to practise in Electrochemistry

Concept Revision

Revise definitions, principles, equations, trends and core ideas from Electrochemistry before attempting MCQs.

Exam-style MCQs

Use chapter-focused multiple-choice practice to improve accuracy, recall and application for CBSE Class 12 Chemistry.

Performance Practice

Attempt ChemNexa tests, review results and return to weak areas for another round of targeted revision.

Top 20 Electrochemistry MCQs with Answers

These public questions are selected from the exact Electrochemistry chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

1. At equilibrium, the cell potential is:

  • A. Positive
  • B. Negative
  • C. Zero
  • D. Equal to 1 V
Answer: C
Explanation: At equilibrium, ΔG = 0 and therefore Ecell = 0.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

2. In a galvanic cell, oxidation occurs at the:

  • A. Cathode
  • B. Anode
  • C. Salt bridge
  • D. Electrolyte
Answer: B
Explanation: Oxidation always occurs at the anode.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

3. In a galvanic cell, reduction occurs at the:

  • A. Anode
  • B. Cathode
  • C. Salt bridge
  • D. Wire
Answer: B
Explanation: Reduction always occurs at the cathode.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

4. Electrons in a galvanic cell flow through the external circuit from:

  • A. Cathode to anode
  • B. Anode to cathode
  • C. Salt bridge to anode
  • D. Electrolyte to wire
Answer: B
Explanation: Electrons are released at the anode and consumed at the cathode.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

5. For a spontaneous galvanic cell under standard conditions, E°cell is:

  • A. Negative
  • B. Positive
  • C. Zero
  • D. Infinite
Answer: B
Explanation: A spontaneous cell reaction has positive standard cell potential.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

6. The relation between standard Gibbs energy and cell potential is:

  • A. ΔG° = nFE°
  • B. ΔG° = -nFE°
  • C. ΔG° = RT/E°
  • D. ΔG° = E°/nF
Answer: B
Explanation: Electrical work gives ΔG° = -nFE°.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

7. During electrolysis, oxidation occurs at the:

  • A. Cathode
  • B. Anode
  • C. Both
  • D. Electrolyte bulk only
Answer: B
Explanation: Anions lose electrons at the anode.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

8. The standard electrode potential of the standard hydrogen electrode is:

  • A. 1.00 V
  • B. 0.00 V
  • C. -1.00 V
  • D. 0.76 V
Answer: B
Explanation: The SHE is assigned E° = 0.00 V by convention.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

9. For a spontaneous cell reaction, ΔG° is:

  • A. Positive
  • B. Negative
  • C. Zero
  • D. Undefined
Answer: B
Explanation: Spontaneity requires ΔG° < 0.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

10. The Nernst equation relates electrode potential to:

  • A. Only temperature
  • B. Reaction quotient and temperature
  • C. Only pressure
  • D. Only current
Answer: B
Explanation: The Nernst equation includes E°, T, n, and reaction quotient Q.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

11. The relation between E°cell and equilibrium constant K is:

  • A. E° = -(RT/nF)lnK
  • B. E° = (RT/nF)lnK
  • C. E° = nF/RT
  • D. E° = KRT
Answer: B
Explanation: From ΔG° = -nFE° and ΔG° = -RTlnK, E° = (RT/nF)lnK.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

12. Molar conductivity is defined as conductivity multiplied by:

  • A. Molar mass
  • B. Volume containing one mole of electrolyte
  • C. Resistance
  • D. Cell constant only
Answer: B
Explanation: Λm = κ × volume containing 1 mol electrolyte.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

13. Molar conductivity of a strong electrolyte on dilution generally:

  • A. Decreases sharply
  • B. Increases slowly
  • C. Remains constant
  • D. Becomes zero
Answer: B
Explanation: Ion interactions decrease on dilution, so Λm increases gradually.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

14. Molar conductivity of a weak electrolyte on dilution:

  • A. Decreases
  • B. Increases sharply
  • C. Remains unchanged
  • D. Becomes negative
Answer: B
Explanation: Dilution increases ionisation as well as reducing ion interactions.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

15. Electrolysis of molten NaCl gives sodium at the:

  • A. Anode
  • B. Cathode
  • C. Salt bridge
  • D. Both electrodes
Answer: B
Explanation: Na⁺ gains electrons at the cathode.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

16. Conductance is the reciprocal of:

  • A. Resistivity
  • B. Resistance
  • C. Conductivity
  • D. Cell constant
Answer: B
Explanation: G = 1/R.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

17. The SI unit of conductivity is:

  • A. S m⁻¹
  • B. S cm² mol⁻¹
  • C. ohm
  • D. V m⁻¹
Answer: A
Explanation: Conductivity has SI unit siemens per metre.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

18. Kohlrausch's law states that at infinite dilution:

  • A. Ions do not conduct
  • B. Each ion contributes independently to total molar conductivity
  • C. Only cations conduct
  • D. Only anions conduct
Answer: B
Explanation: At infinite dilution, ionic contributions are independent.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

19. The cell constant is equal to:

  • A. A/l
  • B. l/A
  • C. RA
  • D. κR
Answer: B
Explanation: Cell constant = distance between electrodes / electrode area.

CBSE Class 12 Chemistry · Electrochemistry · Very Very Hard

20. Faraday's first law states that deposited mass is proportional to:

  • A. Current only
  • B. Time only
  • C. Charge passed
  • D. Voltage
Answer: C
Explanation: m ∝ Q = It.

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Electrochemistry Practice Tests

Electrochemistry Frequently Asked Questions

What should I revise first in Electrochemistry?

Start with oxidation and reduction, electrode notation, anode/cathode conventions and standard electrode potential. Then move to the Nernst equation, conductance and electrolysis.

Why is the Nernst equation important?

It relates electrode or cell potential to concentration and the reaction quotient, so it is central to many conceptual and numerical electrochemistry problems.

How should I practise Electrochemistry MCQs?

Mix direct concept questions with short calculations. Review every wrong answer and identify whether the error came from a sign convention, unit conversion, formula choice or concept gap.

Continue with another chapter to build connected concepts and strengthen your overall Chemistry preparation.

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