Deep-Dive Guides · Redox & Electrochemistry

Redox & Electrochemistry (Inorganic) — the complete deep dive

The whole topic is one idea drawn five ways: how badly each species wants electrons.

Free extract — the opening section of the guide, in full.

0. The big picture — potential as electron appetite

A redox reaction is an electron auction: the couple with the more positive reduction potential wins the electrons and gets reduced; its partner is oxidised. Everything else is bookkeeping around that single fact. Five questions recur, and each has one tool that answers it best:

Question	Best tool	Key operation
Is this reaction spontaneous / how big is K?	E°, ΔG = −nFE	sign of E°_cell; log K = nE°/0.0592
What is E at non-standard conditions?	Nernst	E = E° − (0.0592/n)log Q
What is a stepwise or skip-step potential?	Latimer	weight by electrons: E° = Σn_iE_i/Σn_i
Which oxidation state is most stable / disproportionates?	Frost	lowest point = most stable; convex = disproportionates
Which species is stable at a given E and pH?	Pourbaix	read the domain; slope = H⁺/e⁻ coupling

The one rule people get wrong: E° is an intensive property — it does not scale when you multiply a half-reaction. To combine couples you must add the extensive quantity ΔG = −nFE° (equivalently, add the products n·E°), then divide by the new total n. Never average two potentials.

Read the rest of this guide

The remaining 10 sections — Thermodynamics: E°, ΔG, combining couples, The Nernst equation & its uses, Latimer diagrams, Frost (Ebsworth) diagrams and more — are part of ChemVidya Full Access, along with the other guides, the books, the study notes and 6,000+ practice questions with worked solutions.

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