Surface tensions and densities of concentrated aqueous solutions of citric acid

Abstract Surface tensions of aqueous solutions of citric acid (unsaturated solutions and solutions with microcrystals) were measured in the temperature range from 283.15 K to 323.15 K. They were determined by the pendant drop method. Their values are compared with those that exist in the literature. Together with measured surface tensions, the corresponding densities were also determined by using an oscillating tube densimeter. Basing on measured densities and surface tensions, the parachor values and apparent molar volumes of aqueous citric acid solutions were calculated and discussed.