Electrochemistry
Electrochemical cells, Nernst equation, conductance
Key Concepts
- Galvanic (voltaic) cell: spontaneous redox reaction generates electricity
- Electrolytic cell: non-spontaneous reaction driven by external electricity
- Standard hydrogen electrode (SHE): E° = 0 V (reference)
- Higher reduction potential → stronger oxidising agent
- Faraday's laws: mass deposited proportional to charge passed and equivalent weight
Important Formulae
| Cell EMF | E_cell = E°_cathode − E°_anode |
| Nernst equation | E = E° − (RT/nF) ln Q |
| ΔG and EMF | ΔG° = −nFE° |
| Faraday's first law | m = (M/nF) × Q = (M/nF) × It |
| Kohlrausch's law | Λ°_m = Σ(λ° ions) |
Quick Tips
- Faraday constant F = 96,485 C/mol ≈ 96,500 C/mol.
- At equilibrium: E_cell = 0; ΔG = 0; Nernst gives E° = (RT/nF) ln K.
- Specific conductance decreases on dilution; molar conductance increases.
Sample Practice Questions
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Faraday's first law: mass deposited m = :
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Answer: ZIt (Z = electrochemical equivalent)
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Galvanic cell converts:
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Answer: Chemical energy to electrical energy
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During charging of a lead-acid battery, PbSO₄ at anode converts to:
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Answer: PbO₂
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Nernst equation: E = E° − (RT/nF) ln Q. At 25°C with n=1:
Show answer
Answer: E = E° − 0.0592 log Q
Practice Questions
Practice 20 randomly selected NEET questions on Electrochemistry. Answers are revealed after each question.
Start Practice →Frequently Asked Questions
What are the key concepts in Electrochemistry for NEET?
Galvanic (voltaic) cell: spontaneous redox reaction generates electricity; Electrolytic cell: non-spontaneous reaction driven by external electricity; Standard hydrogen electrode (SHE): E° = 0 V (reference); Higher reduction potential → stronger oxidising agent; Faraday's laws: mass deposited proportional to charge passed and equivalent weight.
Which formulae are important for Electrochemistry in NEET?
Cell EMF: E_cell = E°_cathode − E°_anode; Nernst equation: E = E° − (RT/nF) ln Q; ΔG and EMF: ΔG° = −nFE°; Faraday's first law: m = (M/nF) × Q = (M/nF) × It; Kohlrausch's law: Λ°_m = Σ(λ° ions).
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