Debye HUckel Theory

Debye - Huckel Theory:

They proposed a theory for dilute solutions of Strong Electrolytes.

To explain the behaviour of dilute solutions of strong electrolytes ,they used the theories which are governing macroscopic as


 * )Kinetic molecular theory


 * )Thermodynamics aspects.

Postulates of Debye Huckel Theory:

1) The dilute solutions of strong electrolytes are completely ionized.The properties of solutions observed are due to unequal distribution of ions resulting in interionic interactions.

2)They showed that because of electrostatic attraction between charged ions, each positive ion in the solution is surrounded by more negative ions and vice versa.

In other words, each in the solution is surrounded by ionic atmosphere whose net charge is opposite to central ion.

3)The properties of electrolytes are described by the interaction of central ion and its ionic atmosphere.

4)Since, the nature of atmosphere is decided by the valance of ion, the concentration of electrolyte, temperature, and dielectric constant of medium.

These are also the properties controlling thermodynamic behaviour of solutions