In 1887, Arrhenius put forwarded a theory to explain the properties of electrolysis of solution.
Postulates of Arrhenius theory of ionization:
- When an electrolyte is dissolved in water, it dissociates into oppositely charged particles called ions and the process is called ionization.
- The positively charged ions are called cations and the negatively charged ions are called anions.
- The total positive charge present in the cations is equal to the total negative charge in anions. So, the electrolytic solution is electrically neutral.
- If electricity is passed through the electrolytic solution, cations moves towards the cathode and anions move towards anode. This is the reason for the electrical conductivity of electrolytic solution.
- The ions given by the electrolyte have tendency to reunite to form undissociated molecule thereby establishing an equilibrium between ions and undissociated molecules called the ionic equilibrium.
- The ionization is an incomplete process and the extent of ionization is measured in terms of degree of ionization.