Role of solvent nucleophilicity in excess-acidity plots for equilibria in sulfuric acid – water mixtures
Bibliographic record
Abstract
For protonation of a base B to give BH+ and for reaction of carbocations R+ with water to give ROH in a range of sulfuric acid – water mixtures, slopes of excess-acidity plots of equilibrium data are discussed. Formal connections between the excess-acidity approach and the Grunwald–Winstein (GW) and extended GW equations, noted previously by Bagno et al., are evaluated. It is proposed that a major factor is variations in the solvent dependence of the rates of reactions of the cations (BH+ or R+) with water in the sulfuric acid – water mixtures. Rates of reactions of more stable cations (e.g., Ph3C+) with water are more sensitive to changes in solvent nucleophilicity, and the lower nucleophilicity of the water in sulfuric acid – water mixtures leads to an increase in [BH+]/[B] or [R+]/[ROH] concentration ratios (and hence to greater slopes m* in excess-acidity plots).Key words: excess acidity, sulfuric acid, kinetics, solvent nucleophilicity, solvolysis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".