Degree of dissociation (degree of ionization):-

It may be defined as the fraction of total no. of molecules of an electrolyte which ionizes into ion.

If value of ∝ = 0.99, it is strong electrolyte.

Let us consider weak acid

K = C∝²

Hence, Ostwald’ dilution law states the degree dissociation of any weak electrolyte is inversely proportional to the square root of molar concentration & directly proportional to the square root of dissociation constant or ionization constant of acid.