Solutions in selenic acid. Part III. Correlation of acidities (H 0) of aqueous selenic and sulphuric acids

Abstract

A number of benzophenone derivatives have been used as indicators in spectrophotometric determination of acidity functions, H0, of 50–95 %(w/w) solutions of selenic acid in water at approximately 25°. Two of the indicators were studied in sulphuric as well as selenic acid. The proton-donating power of selenic acid is approxmately 92% that of the sulphuric acid in the range 45–75 %(w/w). Steps were taken to counter the effects of slow, irreversible reactions between some of the indicators and selenic acid; the specific rates of these reactions are reported.