3. Ionic Equilibrium

Ostwald’s Dilution Law: Degree of Dissociation

Ostwald’s dilution law is the application of the law of mass action to weak electrolytes in solution.

A binary electrolyte AB which dissociates into A+ and B ions.

AB ⇌ A+ + B

(i) For very weak electrolytes, since α <<< 1, (1 – α) = 1​

∴ K=C\alpha^2K=KV

(ii) Concentration of any ion = Cα = √CK = √K/V

Degree of ionization increases on dilution. Thus, degree of dissociation of a weak electrolyte is proportional to the square root of dilution.

Leave a Reply

Your email address will not be published. Required fields are marked *