<b>Study of Intermolecular Interactions through Freelength, and Internal Pressure of Ternary Liquid Mixture of Alcohol, Formic Acid and Tri Ethyl Amines</b> Ultrasonic velocities, Densities and Viscosities are measured for ternary liquid mixture of formic acid and tri ethylamine TEA with ethanol. From this experimental data freelength, excess freelength, internal pressure and excess internal pressure have been calculated. The behaviour of mixture has been investigated at 303K, 308K and 313K for frequency 2Mz. These parameters have been discussed to throw light on intermolecular interactions between the components of ternary mixture. molecular interactions, hydrogen bonding, freelength, internal pressure, ternary liquid mixtures, TEA, carboxylic acids 701-705 Issue-5 Volume-1 P J Thakare | J B Thakare | N G Belsare