Ultrasonic velocities, relative permittivities and refractive indices for binary liquid mixtures of trichloroethene with pyridine and quinoline

Ultrasonic velocities, u, relative permittivities, ε, and refractive indices, n, have been measured for binary liquid mixtures of trichloroethene (CHClCCl2) with pyridine (C5H5N) and quinoline (C9H7N) at 303.15 K. The relative-permittivity data have been used to calculate total molar polarisations, P, for the various systems. The quantities ΔkS and ΔP which refer, respectively, to the deviations of the isentropic compressibilities and total molar polarisations of the mixtures from the values arising from the mole fraction mixture law, have been calculated. The apparent molar polarisations, PD, of C5H5N and C9H7N have also been calculated in CHClCCl2. The values of ΔkS, ΔP and PD show that CHClCCl2 forms intermolecular complexes with C5H5N and C9H7N in the liquid state. The values of the equilibrium constant, Kf, for the formation of 1:1 complexes of CHClCCl2 with C5H5N and C9H7N, as calculated using relative permittivity data, are in accord with the theory based upon electrostatic interactions of the solute with the liquid.