Original Articles
K. Renuka Devi and S. Rathika
Abstract
Nitrogen is needed by all plants and usually in large quantities. In fact, nitrogen is so important to plant growth and thus to food and fiber productions. Urea is the world’s most common nitrogen fertilizer and has been used uniformly in all the agricultural lands of the world. Urea is soluble compound and easily gets along with water. The chemical structure of urea helps it to be soluble enough as the hydrogen bonds with water molecules, each forming two bonds with oxygen. In the present work, ultrasonic velocity, density and viscosity of aqueous solutions of urea were measured at various temperatures from 303°K to 323°K. The internal pressure (πi), osmotic pressure (π), free volume (Vf), Δπi, molar cohesive energy (MCE), gibb’s free energy (ΔG) of the solutions were computed. From the variations of the values with the concentration and temperatures of the solutions the interaction between water and urea is studied. The concentration dependence of viscosity was explained by Jones-Dole equation. The coefficients A and B the above equation have been studied at different temperatures. Δπi has been evaluated in each system which gives an idea about the effect of cohesive forces in ion-solvent interaction. It is understood that sensitive information regarding the cohesive forces is well obtained by the data Δπi instead of the coefficients A and B of the Jones-Dole equation.