Physico-chemical studies of different solutions of electrolytes such as chlorides of Fe3+, Co3+, Cu2+, Mg2+, Hg2+ and Ni2+ in methanol-water and ethanol-water system

Abstract

The study of structure of water and of aqueous solutions of electrolytes and non-electrolytes are important from both theoretical and practical points of view. Water structure plays an important role in aqueous systems. The knowledge of water structure is a prerequisite to understand the various interactions in the aqueous solutions. In this investigation, the experimental measurements of density and viscosity of aqueous solution of FeCI3• CoCh, CuCh, MgClz, HgCh and NiCh (electrolytes) in the presence of methanol and ethanol were carried out at different temperature (S-3S°C). Here, some parameters related to density and viscosity, such as B-coefficients of Jones- Dole equation, excess molar volume VmE, apparent molal volumes, enthalpy of activation ~H'1#'free energy of activation ~G'1#and entropy of activation, T~S'1#for viscous flow were calculated by using standard equation in order to investigate the effect of methanol and ethanol on the structure modifying properties ofFeCh. CoCh, CuClz,MgCJz,HgClz and NiCh (electrolytes) on water. In this study the values apparent molar volumes of all solutions are found positive and increase almost linearly with increase mole fraction of electrolytes both in methanol-water and ethanol-water system. The experimentally determined viscosity values of different solutions were found to decrease with increase of temperature. The positive values of Bcoefficient for the solution containing trivalent cation such as Fe3 +, C03 + were observed higher than those of bivalent cation such as Mg z +, Cu z + etc. The positive values indicate that the electrolytic salts taken in this study are structure maker. The structure intensifying properties of these electrolytes were also supported by the calculated values of thermodynamic quantities such as ~H'1#'~G'1#and T~S'1#'