Abstract: Ultrasonic velocity has been measured using an automatic pulseecho velocimeter at various temperatures in nitric acid at various concentrations ranging from 20 to 99 per cent of weight.The various parameters,such as molar sound velocity,specific acoustic impedance,adiabatic compressibility,intermolecular free length for the solution and the ultrasonic velocity of pure nitric acid,have been computed from the measurement results.Excess ultrasonic velocity,excess molar volume,excess adiabatic compressibility and excess intermolecular free length have also been calculated.The results show that with increasing concentration of nitric acid the strength of ion-ion interaction in the solution may increase to a maximum and then decreases.