Electrochemistry

Redox

• Oxidation: loss of electrons (increase in oxidation number).
• Reduction: gain of electrons. Remember OIL RIG.

Electrochemical series and cells

Standard electrode (reduction) potentials E° are measured against the hydrogen electrode (0.00 V).

• More negative E° → stronger reducing agent (e.g. Zn, -0.76 V).
• More positive E° → stronger oxidising agent (e.g. Cu²⁺/Cu, +0.34 V).
• E°cell = E°(reduced species) - E°(oxidised species). For Zn/Cu: 0.34 - (-0.76) = 1.10 V.
• A positive E°cell means the reaction is feasible.