Study of the Effects of Electrolytes on the Carbohydrate Solutions with Volumetric and Viscometric Measurements

Abstract

In this study, a simple volumetric and viscometric method was used for the analysis of effect of body containing electrolytes such as NaCl and KC1 on the carbohydrates (glucose, sucrose and maltose) solution. The densities and viscosities of NaCl and KCI at different concentration in aqueous and aqueous glucose, aqueous sucrose and aqueous maltose (1% (w/v), 5% (w/v) and 10% (w/v)) solutions have been determined at 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K respectively. The studied electrolytes are found to be dissolved readily in aqueous and aqueous carbohydrate (upto 10% (w/v)) solutions. The density of glucose, sucrose and maltose in aqueous solution were found to be order of Maltose > Sucrose > Glucose. The value of density of NaCl and KCI increases with the increasing of molarity of the electrolytes. Densities of electrolytes in aqueous carbohydrate solutions are concentration of electrolyte can be attributed to solute-solvent interaction. The apparent molar volumes, ɸv were obtained from these densities data. The limiting apparent molar volumes, ɸºv and experimental slope, Sv derived from Masson equation have been interpreted in terms of solute- solvent interactions. The sign of --- i.e. second [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P derivative of limiting apparent molar volume of solutions with respect to temperature at constant pressure which corresponds to structure making or breaking properties of solutes were determined. NaCl in water, 1% (w/v) glucose and 1% (w/v) maltose solution, the value of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P were found to be slightly positive suggesting structure making property. In case of sucrose it shows negative value of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P for all the electrolytes containing solvent systems indicating structure breaking property. KCI in water and carbohydrate solution, the values of [(∂^2 〖 Ø v 〗^ )/(∂〖 T 〗^2 )]P were found to be negative suggesting structure breaking tendency. The viscosity vs molarity plots for all the electrolytes systems are linear in all the solvent systems with some exceptions. The viscosity, ƞ for all the studied electrolytes are greater in aqueous carbohydrate solvent system than those in water system. The viscosities coefficients A and B were determined from viscosities data on the basis of Jones Dole equation. The coefficient B gives information regarding solute - solvent interaction and shape and size effect on the solvent structure. The coefficient A represents the ion-ion interaction. The B-coefficient for NaCl in aqueous and aqueous glucose, aqueous sucrose and aqueous maltose solutions (1% (w/v)) at all the temperatures are positive. The positive value of the B-coefficient corresponds to the structure making behavior of solutes. The B-coefficient for KC1 in water and carbohydrate solutions (1%, 5% and 10% (w/v)) are negative. The negative value of B-coefficient corresponds to the structure breaking behavior of KCl. The sign of dB/dT corresponds to structure making or breaking properties of solutes, were determined. For NaCl in aqueous and aqueous carbohydrates (1% (w/v)) solutions, the values of dB/dT are negative which corresponds to structure making behavior. For aqueous and aqueous carbohydrate solution (1%, 5% and 10% (w/v)) of KC1, the values of are positive which corresponds structure breaking behavior.The free energy of activation, ΔG≠ for viscous flow was calculated using Nightinagle and Benck equation at the experimental conditions. Activation enthalpy, ΔH≠ and activation entropy, ΔS≠ were calculated using the Eyring equation and other thermodynamic relations. The effects of electrolytes on the structure of water and aqueous carbohydrate solutions were interpreted in terms of apparent molar volumes, viscosities and viscosity coefficients (A and B) values and thermodynamic parameters (ΔG≠, ΔH≠, ΔS≠).