The degree of dissociation α may be calculated for any concentration c of the electrolyte using the equation where f± is the mean activity coefficient of the electrolyte (see alsoOSTWALD DILUTION LAW). The degree of dissociation can then be calculated from the ICE tables at the top of the page for the dissociation of N 2 O 4 (g): K p = 4 α 2 1 − α 2 (p t o t) 0.323 a t m = 4 α 2 1 − α 2 (1.00 a t m) The degree of dissociation (α) of a weak electrolyte ,A x B y is related to van't Hoff factor (i) by the expression Electrolyte Power Compounds that completely dissociate is characterized by α>30% and is called strong electrolytes. Electrolyte characterized by 3<α<30% is medium electrolyte. 17 If the degree of dissociation is α<3% than electrolyte is called weak electrolyte. The classical theory of electrolytic dissociation is applicable only to dilute solutions of weak electrolytes. The degree of dissociation `(alpha)` of a weak electrolyte, `A_(x)B_(y)` is related to van't Hoff's factor `(i)` by the expression: