The ultrasonic velocity, density and viscosity have been measured for the mixtures for the ternary system of n–alkanols, namely, 1–propanol, 1–butanol, and 1–pentanol in cyclohexane with N- N dimethyl formamide (DMF) at 303K. From these data, some of the acoustical parameter such as adiabatic compressibility (b), freelength (Lf), free volume (Vf) and internal pressure (pi) have been measured. The excess values of the above parameters are also evaluated and presented. The results have been analysed and interpreted in terms of molecular association such as hydrogen bonding formed between 1-alkanol and DMF. Further, such addition of DMF makes dissociation of associated structure of 1-alkanols. The observed excess values predict weak interactions in the present systems
