ELECTRICAL-CONDUCTIVITY ANOMALY IN BINARY-LIQUID MIXTURES NEAR THE CRITICAL-POINT

The electrical conductivity (sigma) of the three binary liquid mixtures (a) CH3OH + CS2, (b) C6H5NO2 + C6H14 and (c) C6H5NH2 + C6H12 has been determined at various temperatures starting from the one-phase region down to critical temperature (T(c)) at 400 kHz. It is observed that the critical exponent 0 of the conductivity singularity near T(c) has no appreciable dependence upon the operating frequency. Thus any contribution from dielectric dispersion to the electric conductivity is negligible. Therefore it is concluded that there is a singular contribution to the electrical conductivity which is characterised by an exponent THETA = 0.72 in binary liquid systems.