what is debye huckel onsagers equation?

Debye-Huckel treatment deals with the distribution of ions around a given ion and the net effects of these neighboring ions have on the central ion. Debye and Huckel derived an equation based on the quantitative treatment of inter ionic attraction. This equation was later on modified by Onsagar and is known as Debye-Huckel-Onsagar (DHO) equation for strong electrolyte. It shows how the potential energy of an ion in solution depends on the ionic strength of the solution. In the case of strong electrolytes the value of molar conductance at infinite dilution is much less than unity.

Onsager was able to derive a theoretical expression to account for the empirical relation known as Kohlrausch's Law, for the molar conductivity, Λm.

Lambda_m =Lambda_m^0-Ksqrt{c}

Lambda_m^0is known as the limiting molar conductivity, K is an empirical constant and c is the electrolyte concentration Limiting here means "at the limit of the infinite dilution"). Onsager's expression is

Lambda_m =Lambda_m^0-(A+BLambda_m^0 )sqrt{c}

where A and B are constants that depend only on known quantities such as temperature, the charges on the ions and the dielectric constant and viscosity of the solvent. This is known as the Debye-Hückel-Onsager equation

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4n+e     n=2,3,4,5............ 

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^m = ^m* -b(c)1/2

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