𝔖 Bobbio Scriptorium
✦   LIBER   ✦

The applicability of Hammett's acidity function H0 to solutions in methanol-water mixtures

✍ Scribed by C. L. de Ligny; H. Loriaux; A. Ruiter

Book ID
104586348
Publisher
Elsevier Science
Year
2010
Tongue
English
Weight
561 KB
Volume
80
Category
Article
ISSN
0165-0513

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The dissociation constants of 4‐aminoazobenzene‐4′‐sulphonic acid, 4‐(methylamino)azobenzene‐4′‐sulphonic acid, 4‐(phenylamino)‐azobenzene‐4′‐sulphonic acid, 4‐(dimethylamino)azobenzene‐4′‐sulphonic acid and p‐nitrophenol were determined in water and in several mixtures of methanol and water at 25°. The influence of the percentage of methanol on the dissociation constant differs greatly for the various indicators, even for indicators of the same charge type.

From this it follows that Hammett's acidity function H~0~ for solutions in mixtures of methanol and water depends on the indicator used for determining H~0~. Thus, for solutions in mixtures of methanol and water and presumably also in mixtures of water and other non‐electrolytes, H~0~ is not a useful, unambiguous measure of the acidity.

📜 SIMILAR VOLUMES

The pH of some standard solutions in met
The pH of some standard solutions in methanol and methanol-water mixtures at 25° I. Theoretical Part
✍ C. L. de Ligny; P. F. M. Luykx; Miss M. Rehbach; Miss A. A. Wieneke 📂 Article 📅 2010 🏛 Elsevier Science 🌐 English ⚖ 600 KB

## Abstract It has been shown that pH\* values, determined by the electrometric method in solvents other than water, can be interpreted as ‐log __m__~H~γ\*~H~ if the pH meter is standardized by means of a standard solution in the same solvent. The pH\* of standard solutions in methanol and methanol

The pH of some standard solutions in met
The pH of some standard solutions in methanol and methanol-water mixtures at 25° II. Experimental Part
✍ C. L. de Ligny; P. F. M. Luykx; Miss M. Rehbach; Miss A. A. Wieneke 📂 Article 📅 2010 🏛 Elsevier Science 🌐 English ⚖ 563 KB

## Abstract By application of a method which was developed in Part I of this series the pH\* of an oxalate and a succinate buffer in water, methanol‐water mixtures and methanol and that of a salicylate buffer in methanol was measured. The pH\* in methanol was measured by application of both silver