Temperature and concentration dependences of the electrical conductance, diffusion and kinetic parameters of selenium dioxide solutions in ordinary and heavy water

• Published in: Journal of solution chemistry 2007-02, Vol.36 (2), p.171-192
• Main Authors: VLAEV, Lyubomir, TAVLIEVA, Mariana, BESTER-ROGAC, Marija
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Solutions
• ISSN: 0095-9782; 1572-8927
• DOI: 10.1007/s10953-006-9105-2

On the basis of conductivity studies, empirical equations describing the temperature and concentration dependences of the electrical conductance of Se02 solutions in ordinary and heavy water were derived. Values of the equivalent conductivity of ions at infinite dilution, the first dissociation constant of selenous acid in the temperature region 12 to 45DGC and the thermodynamic parameters of the dissociation process were determined. Using these values, the absolute mobility, the transport numbers of the ions and their diffusion coefficients were calculated. Furthermore, the values of the transition energies D EDG for the ions were calculated at different temperatures. The dependencies observed were interpreted using Samoylov's theory for positive/negative hydration of the ions. It was shown that the HSe03 and DSe03 ions were positively hydrated and stabilized the solvent structure, but these effects diminished with an increase of the temperature. The temperature dependences of the hydration numbers and the effective ionic radii were determined. The values of the changes of the Gibbs energy, entropy and enthalpy for the transitions of ions from one quasi-equilibrium state to another were calculated at different temperatures.