English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A method is described to differentiate between completely and incompletely dissociated acids by means of measurements of the emf of galvanic cells without liquid junctions. Hydrogen and silver-silver-chloride electrodes and solutions of the acid, its sodium or potassium salt, and sodium or potassium chloride are used. The activity coefficients of hydrochloric acid in such mixtures are calculated by the equation relating the emf to the activity of hydrochloric acid in known concentrations of the acid and salts. If the mean values of the activity coefficient of hydrochloric acid in the mixtures are higher than those predicted by the limiting law of Debye and Hiickel, the acid is then considered to be completely dissociated. If they are lower, the acid is incomplet ely dissociated. By this method it was found that the sulfonic acid group in p-phenolsulfonic and 4-chlorophenol-2sulfonic acids may be regarded as completely dissociated into sulfonate and hydrogen ions at temperatures of 10°, 25°, 40°, and 60° C. . Solutions containing p-phenolsulfonic acid, its sodium or potassium salt, and sodium or potassium chloride and solutions containing 4-chlorophenol-2-sulfonic acid, its sodium salt, and sodium chloride are suitable for use as pH standards. Their pH values range from 1.2 to 2.5 and vary only slightly with temperature changes. Directions for their preparation are given. The significance of t he complete dissociation of the sulfonic acid group in the calculation of the ionization constants and pH values of sulfonate buffers and indicators is discussed in t erms of the tautomeric relations and the theory of color changes of indicators.

pH values of acid-salt mixtures of some aromatic sulfonic acids at various temperatures and a criterion of completeness of dissociation