Debye- Huckel Onsager Theory
In case of weak electrolytes the increase in equivalent conductance with dilution can be easily explained on the basis of
Arrhenius theory, according to which the conductance increases due to increase in dissociation of weak electrolyte with dilution. But this explanation cannot be applied in case of strong electrolytes like NaCl as they are almost completely dissociated into constituent ions (Na
+ and Cl
−) even at moderate concentration.
Peter Debye and Huckel in 1923 initially derived an equation to describe how the equivalent conductance of electrolytic solution changes on dilution. Later this equation was further improved by Onsager and now this equation is known as Debye Huckel Onsager equation.
Debye-Huckel-Onsager Theory is based on the following Assumptions-
1. Strong electrolytes are completely dissociate into their constituent ions in solution.
2. Due to Coulornbic forces between the charges of the ions, they do not behave like molecules in their transport and thermodynamic properties.
Read More