A-Level Chemistry: Redox & Electrochemistry: Cell Potentials

Redox basics

Oxidation is loss of electrons, reduction is gain. Remember OIL RIG. Balance redox equations by ensuring both charge and atoms balance.

Common oxidising/reducing agents

• Oxidising: acidified KMnO₄ (purple → colourless), acidified K₂Cr₂O₇ (orange → green).
• Reducing: Zn, Fe²⁺, iodide.

Exam habits

• Always write oxidation states above atoms.
• Check colour changes in ionic eqns (often asked).
• Acidic vs alkaline medium changes balancing method.