Thermodynamics of Non-Ideality and Ion-Association in Saturated Aqueous Solution of Barium Nitrate at 25° C

Using Solvent Evaporating and Atomic Emission Spectrophotometric methods, the solubility of Ba (NO3 )2 inwater at 25.0 ° C was determined. Activity coefficients, f+ and f_ of Bat) and N0i(aq) ions in the saturatedsolution at 25.0 ° C were estimated upon the extended Debye —Hiickel theory and then, the constantK'sp =[Ba2+1f+ [NO-3 ]2 f 2 was evaluated. Comparing the value of thermodynamic solubility product constant,Ksp(th) ,of Barium Nitrate, Ks") =exp (—AG ° / RI) , to the value of K'sp revealed a great difference.The difference has satisfactorily been explained using a combination of Debye-Hackel theory and ionassociationtheory.