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In the present study the,the theoretical ultrasonic velocities in the binary mixtures (1) Toluene with Heptan-1-ol, Octan -1-ol and Decan-1-ol (ii) Mehtylbenzene with Hexan-2-ol, Heptan-2-ol and Octan-2-ol and in the ternary (iii)2-Butanol in cyclohexane with toluene have been evaluated using various theoretical relations at different temperatures and compared with experimental values The validity of different theoretical formulae were checked by percentage deviation for all the mixtures at all the temperatures and given in the respective table.The observed deviation of the theoretical velocity from the experimental values show that the molecular interactions between the unlike molecules are responsible for this.The values of the thermodynamic parameters such as Uexp2/Uidl2,molecular interaction (a)acoustic impedance(z) ,relaxation time (t) and intermolecular free length (Lf) as function of mole fraction have been evaluated.Hydrogen bonding in binary and ternary liquid mixtures are discussed in detail.

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