Galvanic Cell vs Electrolytic Cell
⚡ Galvanic Cell
Converts chemical energy → electrical energy. Spontaneous (ΔG < 0). Anode is −ve, Cathode is +ve. Salt bridge maintains electrical neutrality. Example: Daniell cell (Zn-Cu).
🔌 Electrolytic Cell
Converts electrical energy → chemical energy. Non-spontaneous (ΔG > 0). Anode is +ve, Cathode is −ve. Used for electroplating, electrolysis of water, extraction of metals.
The Nernst Equation
E_cell = E°_cell − (0.0591/n) × log Q
At 298K (25°C). n = number of electrons transferred. Q = reaction quotient. At equilibrium, E_cell = 0 and log K = nE°/0.0591. This also connects to: ΔG° = −nFE°
Faraday's Laws — Guaranteed 1 Question
Mass deposited (m) ∝ Charge passed (Q = I × t). m = (M × I × t) / (n × F), where F = 96500 C/mol.
When the same charge passes through different electrolytes, masses deposited are proportional to their equivalent weights (M/n).
Standard Electrode Potential Tips
The more negative the SRP, the stronger the reducing agent. The more positive the SRP, the stronger the oxidizing agent. Always: E°_cell = E°_cathode − E°_anode. If E°_cell > 0, reaction is spontaneous.
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