Dilatometer Studies of the Apparent Molar Volume Limiting Law for High-Charge Electrolytes

Abstract

A continuous-dilution dilatometer, of the tilting type, specifically designed for study of the apparent molar volumes of aqueous electrolytes at low concentrations, is described. Results at 298.16 K have been secured for multivalent (± 3, ± 4, ± 6) univalent electrolytes which demonstrate that the apparent molar volumes vary with c^½ in approximate conformity with the Debye-Huckel limiting-law slopes. Data are presented for: [Co(en)₃] Cl₃, K₃ [CO(CN)₆], [Pt(en)₃] Cl₄, K₄ [Mo(CN)₈]_, [C0{(0H)₂Co(en)₂}₃] (NO₃)₆,Na₆C₆(C00)₆, K₄ [Fe(CN)₆] and [Co(en)₃] (C1O₄)₃ Ion pairing is a significant disturbing factor which hinders treatment of the data in terms of extended forms of the Debye-Huckel equation.