Abstract
Recently, Herráez et al. proposed a new correlation equation, which introduces a correcting polynomial as an exponential-acting upon the molar fraction of one of mixture components. This equation is found to be widely applicable with more reasonable accuracy in systems exhibiting monotonous distribution than those presenting an extremum. In previous works, we have found that the first adjustable parameter of this equation is a universal exponent (0.5 or 1) for dioxane-water and isobutyric acid-water mixtures characterising the presence of solute-solute or solute-solvent interaction at very high dilution. In this work, we have tested this equation in 48 systems, and we have noted that several data on binary mixtures exhibiting monotonous variation are well represented by the two sides of this equation. We have mathematically justified the four distinct values of the universal exponent classifying the nature of each solute-solvent couple in dilute region.