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Electrochemistry WBCHSE Class 12 MCQ & Practice Questions

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

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Electrochemistry Revision Guide for WBCHSE 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 WBCHSE 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 WBCHSE 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.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

1. Standard cell potential is calculated as:

  • A. E°anode/E°cathode
  • B. E°cathode - E°anode
  • C. E°anode - E°cathode
  • D. E°cathode + E°anode always
Answer: B
Explanation: Using reduction potentials, E°cell=E°cathode-E°anode.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

2. Standard cell potential কীভাবে নির্ণয় করা হয়?

  • A. E°anode − E°cathode
  • B. E°cathode − E°anode
  • C. দুইটি যোগ সবসময়
  • D. শূন্য
Answer: B
Explanation: Reduction potentials ব্যবহার করলে E°cell = E°cathode − E°anode।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

3. Cathodic reaction সব electrochemical cell-এ কী?

  • A. Oxidation
  • B. Reduction
  • C. Hydrolysis only
  • D. Neutralization only
Answer: B
Explanation: Cell galvanic বা electrolytic যাই হোক, cathode-এ reduction হয়।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

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

  • A. Zero always
  • B. Imaginary
  • C. Positive
  • D. Negative
Answer: C
Explanation: A spontaneous cell reaction has positive standard emf.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

5. The relation between standard Gibbs energy and cell emf is:

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

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

6. At equilibrium, the cell emf is:

  • A. Infinite
  • B. Always 1 V
  • C. Zero
  • D. Maximum
Answer: C
Explanation: At equilibrium ΔG=0 and therefore Ecell=0.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

7. Galvanic cell-এ oxidation কোথায় হয়?

  • A. Cathode
  • B. Anode
  • C. Salt bridge
  • D. Electrolyte only
Answer: B
Explanation: Electrochemical convention অনুযায়ী oxidation সবসময় anode-এ ঘটে।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

8. ΔG° এবং E°cell-এর সম্পর্ক?

  • A. ΔG°=nFE°
  • B. ΔG°=−nFE°
  • C. ΔG°=RT/E°
  • D. ΔG°=0 always
Answer: B
Explanation: Electrochemical work relation: ΔG° = −nFE°cell।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

9. Kohlrausch law কী বলে?

  • A. Infinite dilution-এ ionic contributions স্বাধীনভাবে additive
  • B. conductivity সবসময় zero
  • C. only metals conduct
  • D. EMF concentration-independent
Answer: A
Explanation: At infinite dilution, each ion contributes independently to limiting molar conductivity।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

10. Oxidation occurs at the:

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

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

11. Reduction occurs at the:

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

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

12. In a galvanic cell, electrons flow externally from:

  • A. Anode to cathode
  • B. Cathode to anode
  • C. Salt bridge to anode
  • D. Electrolyte to wire
Answer: A
Explanation: Electrons released by oxidation at the anode travel to the cathode.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

13. The Nernst equation describes electrode/cell potential under:

  • A. Only standard conditions
  • B. Only zero concentration
  • C. Only equilibrium
  • D. Non-standard conditions
Answer: D
Explanation: It corrects standard potential for activities/concentrations.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

14. Molar conductivity is conductivity multiplied by volume containing:

  • A. One gram of solvent
  • B. One litre of pure water
  • C. One equivalent only
  • D. One mole of electrolyte
Answer: D
Explanation: Molar conductivity represents conductance contribution per mole.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

15. Kohlrausch's law applies to:

  • A. Only metals
  • B. Only non-electrolytes
  • C. Independent migration of ions at infinite dilution
  • D. Only concentrated solutions
Answer: C
Explanation: At infinite dilution each ion contributes independently to limiting molar conductivity.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

16. Limiting molar conductivity is denoted commonly by:

  • A. R
  • B. Λm°
  • C. κ
  • D. ρ
Answer: B
Explanation: Λm° denotes molar conductivity at infinite dilution.

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

17. Galvanic cell-এ reduction কোথায় হয়?

  • A. Anode
  • B. Cathode
  • C. Salt bridge
  • D. Wire
Answer: B
Explanation: Reduction cathode-এ ঘটে।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

18. E°cell > 0 হলে standard অবস্থায় reaction কী?

  • A. Non-spontaneous
  • B. Spontaneous
  • C. Equilibrium only
  • D. Impossible
Answer: B
Explanation: ΔG° = −nFE°; E° positive হলে ΔG° negative, reaction spontaneous।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

19. Molar conductivity Λm-এর SI unit কী?

  • A. S m⁻¹
  • B. S m² mol⁻¹
  • C. Ω m⁻¹
  • D. mol m⁻³
Answer: B
Explanation: Λm conductivity × volume per mole; SI unit S m² mol⁻¹।

WBCHSE Class 12 Chemistry · Electrochemistry · Very Hard

20. Dilution-এ strong electrolyte-এর molar conductivity কী করে?

  • A. কমে
  • B. বাড়ে এবং limiting value-এর দিকে যায়
  • C. শূন্য হয়
  • D. constant
Answer: B
Explanation: Dilution-এ interionic interaction কমে, Λm বৃদ্ধি পেয়ে Λm°-এর দিকে যায়।

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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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