Limitations of Arrhenius theory

Following are the limitations of Arrhenius theory of acid and base:

  1. This theory is limited to aqueous medium only.
  2. According to Arrhenius theory, acids are those which furnish H+ ion in water. H+ ion is a proton which is not capable of independent existence. It may exist as hydronium ion H3O+.
  3. There are number of substances like CO2 , SO₂ , NO2 , SO3 which do not contain H+ ion but behaves as acids. Similarly compounds like CaO, MgO, anhydrous NH3 , Na2CO3 which do not contain OH ion but behave as bases.
  4. Neutralization between HCl and do not involve H+ and OH ions-

NH3  + HCl → NH4Cl (s)

CaO  + SO₂   → CaSO3 (s)

 

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