Thermodynamic and physical properties of pure liquids and liquid mixtures have a lot of importance and interest to both Chemists and Chemical Engineers, from different angles in terms of their applications. The thermodynamic and physical properties help one i. to interpret, correlate and predict thermodynamic properties of mixtures through molecular thermodynamic considerations, ii. to find the applicability of theories of liquids and to predict the properties of mixtures of similar nature and iii. to design the industrial equipment with better precision, thus reducing the capital costs. The excess thermodynamic properties are extensively used to study the deviation of a real liquid mixture from ideality. Thermodynamically an ideal solution is one which obeys the generalized form of Raoult's law defined in terms of fugacities. According to this law the fugacity, fi of any component is equal to its mole fraction xi multiplied by its fugacity in the pure state.This book is useful to those wish to do research in Chemistry and Chemical engineering .This book broadly contains research activity of Excess volumes,Excess enthalpies, Solid-liquid equilibria and sound velocities.