Chapter VI - Mixing Schemes in Aqueous Solutions of Nonelectrolytes

Abstract

We apply the same methodology used in Chapter V to aqueous solutions of general nonelectrolytes designated as the ith component. By the mole fraction dependence pattern of the enthalpic interaction function, Hi-iE, we clearly define hydrophobe, hydrophile, and amphiphile for the solute (i). We show the Koga Lines also exist in aqueous solutions of hydrophilic solutes and their extrapolation to the infinite dilution point to the same unique temperature regardless of the kind and identity of solute. This connects smoothly to the subtle crossover in molecular organization of pure H2O that will be discussed in Section [VI-9]. We present the fourth derivative quantity for the first time and its power for identifying the mixing scheme boundary for hydrophilic nonelectrolyte and the subtle crossover for pure H2O which otherwise show very subtle changes. Furthermore, the oddity of aqueous 2-butoxyethanol (BE) left unresolved in the previous chapter is understood more clearly by using the fourth derivative quantity.