10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 1 2016 (January - March) The study of the properties of aqueous solutions is very important in many areas of science and researchers are progressing in this direction with a view to know more about the water structure. The ultrasonic velocity measurements are helpful to study the ion-solvent interaction in aqueous and non-aqueous solutions. The ammonical fertilizers of ammonium sulphate and ammonium chloride contain the nutrient nitrogen in the form of ammonium or ammonia. In this present investigation, ultrasonic velocity, density and viscosity of aqueous fertilizer solutions of ammonium sulphate and ammonium chloride were measured at various temperatures from 303ËšK to 323ËšK. The molal hydration number (n lessThan sub greaterThan h lessThan /sub greaterThan ), molar hydration number (n lessThan sub greaterThan h lessThan /sub greaterThan lessThan sup greaterThan 1 lessThan /sup greaterThan ), apparent molal volume (φ lessThan sub greaterThan v lessThan /sub greaterThan ), apparent molal compressibility (φ lessThan sub greaterThan k lessThan /sub greaterThan ), limiting apparent molal volume (φ lessThan sub greaterThan v lessThan /sub greaterThan lessThan sup greaterThan o lessThan /sup greaterThan ), limiting apparent molal compressibility (φ lessThan sub greaterThan k lessThan /sub greaterThan lessThan sup greaterThan o lessThan /sup greaterThan ), the constants (S lessThan sub greaterThan v lessThan /sub greaterThan & S lessThan sub greaterThan k lessThan /sub greaterThan ) and molar solvated volume (φ lessThan sub greaterThan s lessThan /sub greaterThan ) were determined using the measured values. The study of molar hydration number and molal hydration number reveals that there is a significant interaction between solute and solvent molecules due to which the structural arrangement in the neighbourhood of constituent solutes is considerably affected. K.RENUKA DEVI AND S.RATHIKA : Molal hydration number, apparent molal volume, apparent molal compressibility, limiting apparent molal volume. 270-280