The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride at 25°C and the volume changes on ionization

Abstract

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride are measured up to 2 mol l-1 at 25�C by a combination of pyknometric and dilatometric methods. The apparent molar volume f�V of undissociated ammonia at infinite dilution is found to be 24.85�0.02 cm3 mol-1, and that of NH4Cl is 35.71�0.02 cm3 mol-1. The volume change on ionization for the standard states ΔV� is -29.07�0.04 cm3 mol-1. For aniline the values are: f�V(PhNH2) 89.30, f�V(PhNH3Cl) 102.74 and ΔV� -26.49�0.05 cm3 mol-1.