Partial molal compressibilities of salts in aqueous solution and assignment of ionic contributions

Apparent molal adiabatic compressibilities of a number of 1:1, 2:1, 3:1, and 4:1 electrolytes have been accurately determined in the concentration range 0 to 1 m at 25°C. Debye-Hückel limiting-law behavior is observed in the low concentration region, and a scale of individual ionic compressibilities is proposed in terms of semiempirical calculations based on assessment of the contributions of the various types of solute-solvent interaction in the Frank and Wen model for a series of alkali halides. On this scale, K _s ^o (Cl^?, 25°C)=?17×10^?4 ml-mole^?1 bar^?1. Isothermal compressibility values also have been calculated for a number of the salts studied, and specific effects of hydrophobic interaction and hydrogen bonding on compressibility are indicated.