Molar excess volumes, YE, and molar excess enthalpies, HE, have been determined at 298.15 K by using a dilatometer and an LKB flow mlcrocalorlmeter, respectlvely, for benzene (A), toluene (A), o-xylene (A), m-xylene (A), or p-xylene (A) + o-chlorotoluene (B) mlxtures. While both the YE and the H E values are positive for benzene (A) + othlorotduene (B) mlxtures, they are negative for the rest of the binary mixtures. The data have also been compared wlth the avaliabie literature values. Introductlon Recent years have witnessed considerable interest ( 1-7) in the thermodynamic excess properties of halobenzene (A) + aromatic hydrocarbons (B) mixtures. However, considerable disagreement exists between the H E data reported in the literature (7) for the toluene (A) + o-chlorotoluene (B) mixture.

Molar excess volumes, VE, and molar excess enthalpies, HE, have been measured for acetone (A) + bromoform (B) mixtures at 298.15 and 308.15 K. Results of these measurements suggest the formation of a 1:1 acetone–bromoform molecular complex. The equilibrium constant, K, the enthalpy of formation, ΔH, of the AB complex as also the molar volume change, ΔV, accompanying the complexation reaction [Formula: see text] have been evaluated from the measured HE and VE data. The K value so obtained has further been substantiated by the K value determined for the AB molecular entity from nmr studies on this mixture. Partial molar enthalpy of B (at infinite dilution) in A and vice versa have also been evaluated from the measured HE data at 298.15 K and used to calculate a consistent molar enthalpy of AB complex formation.