Deep-Dive Guides · Acids, Bases & Non-Aqueous Solvents
Acids, Bases & Non-aqueous Solvents — the complete deep dive
"Acid" and "base" are not one idea but a ladder of increasingly general definitions, each built to describe a wider class of reactions.
Free extract — the opening section of the guide, in full.
0. The framework map — which definition is being tested
Each theory was invented to explain something its predecessor could not. Arrhenius is water-bound; Brønsted generalises to proton transfer in any medium; Lewis abandons the proton for electron-pair chemistry; the solvent-system view redefines acid/base relative to whatever solvent autoionises; Lux–Flood handles oxide-ion transfer in melts; Usanovich swallows everything including redox. HSAB sits on top of the Lewis picture as a predictive heuristic for which Lewis acids prefer which Lewis bases.
| Framework | Acid is… | Base is… | Diagnostic clue in a question |
|---|---|---|---|
| Arrhenius | gives H⁺(aq) | gives OH⁻(aq) | aqueous, dilute, "pH" |
| Brønsted–Lowry | proton (H⁺) donor | proton acceptor | conjugate pairs, pKa, any solvent |
| Lewis | electron-pair acceptor (empty orbital) | electron-pair donor (lone pair) | no proton moves; adduct/dative bond forms |
| Solvent-system | increases the solvent cation | increases the solvent anion | named non-aqueous solvent, autoionisation |
| Lux–Flood | O²⁻ acceptor | O²⁻ donor | molten oxides, slags, glasses |
| Usanovich | accepts anions/electrons, gives cations | gives anions/electrons | broadest; includes redox — rarely quantitative |
Read the rest of this guide
The remaining 10 sections — Brønsted–Lowry: proton transfer, Lewis acids & bases, HSAB — hard & soft acids and bases, Non-aqueous solvent systems 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.