Electrochemical and Potential Cells

Cell Diagram

Key Points:

  • Anode: Zinc (Zn)

  • Cathode: Copper (Cu)

  • Electrolyte: Zinc sulfate (ZnSO₄) and copper sulfate (CuSO₄)

  • Cell Potential: Positive voltage indicates spontaneous reaction

  • Electron Flow: From anode (Zn) to cathode (Cu)

  • Salt Bridge: Maintains charge balance by allowing ion flow

  • Applications: Batteries, electroplating, corrosion studies

Half Equations:

Oxidation Reaction: Zn2+ (aq) + 2e ⇌ Zn (s) E° = -0.76 v

Reduction Reaction: Cu2+ (aq)+ 2e ⇌ Cu (s) E° = +0.34 v

Standard Hydrogen Electrode (SHE)

Key Points:

  • Standard Electrode Potential: 0.00 V

  • Reference Electrode: Used to measure other electrode potentials

  • Conditions: 1 M H⁺ concentration, 1 atm H₂ pressure, 25°C

  • Importance: Basis for electrochemical series

  • Applications: Used in pH measurement and electrochemical cells

  • Construction: Platinum electrode in contact with H₂ gas

  • Stability: Highly reproducible and reliable reference point

Half equation:

2H⁺ + 2e⁻ ⇌ H₂ (g)