THERMODYNAMICS OF BINARY-MIXTURES OF NONELECTROLYTES - MOLAR EXCESS GIBBS FREE-ENERGY OF MIXING

Vapour liquid equilibrium data have been measured at 308.15 K for 1,2-dichloroethane (i)+pyridine (j), + alpha-picoline (j), + n-heptane (j) and n-heptane (i) + alpha-picoline (j) mixtures and the same have been utilized to calculate excess Gibbs free energy of mixing G(E). The G(E) data have been analysed in terms of (i) Flory's theory (ii) Sanchez and Lacombe approach and (iii) Graph theoretical approach [using previously reported molar excess enthalpy H(E) (T, X = 0.4 and 0.5) data alone) and it has been observed that the G(E) data evaluated from graph-theoretical approach express the experimental G(E) data better than the data evaluated from the other two approaches.