Electrode Potential - NEET Notes, Formula & Common Mistakes

What NEET Asks

• Conceptual clarity on reduction vs. oxidation potentials.
• Comparing oxidizing/reducing strengths using $E^\circ$ values.
• Predicting reaction feasibility based on standard potentials.

Key Points

• Electrode Potential ($E$): Potential difference at the electrode-electrolyte interface.
• Reduction Potential: Tendency to gain electrons (reduction). IUPAC convention prioritizes reduction potential.
• Oxidation Potential: Tendency to lose electrons (oxidation).
• Relationship: $E_{ox} = -E_{red}$. Example: $E_{red}^{\circ }(Z{n}^{2+}\mathrm{/}Zn)$, so .
• Standard Electrode Potential ($E^\circ$): Potential under standard conditions (1 M, 1 atm, 298 K).
• Standard Hydrogen Electrode (SHE): Reference, $E^\circ = 0.00 V$.

Must-Know Formula / Reaction

• $E_{ox} = -E_{red}$: Oxidation potential is negative of reduction potential.
  • $E_{ox}$: Standard oxidation potential.

Common Mistakes

• Confusing signs: Always use IUPAC reduction potentials. Oxidation potential is its negative.
• Assuming extensive property: Electrode potential is intensive; stoichiometry does not change its value.
• Incorrect strength comparison: More positive $E_{red}^\circ$ means stronger oxidizing agent (easier reduction).

Rapid Revision

Electrode potential is the potential difference at the interface. Reduction potential is standard; oxidation potential is its negative. Higher positive $E_{red}^\circ$ means easier reduction. It's an intensive property, independent of stoichiometry.