Arrhenious theory of Ionization

To explain the conducting power of electrolytes Arrhenius 1887 proposed the theory of ionization called as Arrhenius theory of Ionization.

  • There are the following basic postulates:When electrolyte is dissolved in watre then it spplit it into the two electrically charged particles called as ions. This process of splitting of the electrolytes into ions when it is dissolved in watre is called as ionization or electrolytic dissociation constant.
  • The ion that can be positive charged is called cations and that carry negative charge are called as anions.
  • Electrical conductivity of electrolyte is due to the migration of ions towards the oppositely charged electrodes.
  • Ionization process is reversible process an their occures dynamic equilibrum between ionised and unionised molecules. This means that the molecules are constantly ionizing and ions are  constantly reunited.
  • The ionization process is not 100 %. The ionizatioon process an be explained in terms of degree of ionization .It is the ratio of number of molecules that split ions to the number of molecules that dissolved so
                  α = No of molecules that split into ions / no of molecules that dissolved.
  • The value of alpha is always less than 1. For strong electrolyte it is nearly equal or equal to 1 and for weak electrolyte it is far less than 1.
  • The electrolyte as a whole electrically neutral and the sum of total positively charged on all cations are equal to the total negative charges on all ions.

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