Applicability in Aqueous Solutions:
The Arrhenius theory is strictly applicable only in aqueous solutions where water serves as the solvent. It does not account for acid-base reactions in non-aqueous solvents, which may involve different mechanisms and species.
Incomplete Definition of Bases:
The Arrhenius theory defines bases as substances that produce hydroxide ions (OH-) when dissolved in water. However, there are numerous basic substances that do not contain hydroxide ions, such as ammonia (NH3) and sodium bicarbonate (NaHCO3).
Incomplete Dissociation:
Not all acids and bases completely dissociate in water to produce ions. Some compounds, such as weak acids and weak bases, only partially dissociate, resulting in a partial release of H+ or OH- ions. The Arrhenius definitions do not distinguish between strong and weak acids and bases.
Acid-Base Reactions without Proton Transfer:
The Arrhenius theory focuses solely on proton transfer reactions involving H+ ions. However, there are other types of acid-base reactions that do not involve proton transfer. For example, the reaction of Lewis acids and Lewis bases involves the sharing of electron pairs rather than proton transfer.
Non-aqueous Solvents:
The Arrhenius theory is limited to describing acid-base behavior in aqueous solutions. In non-aqueous solvents, such as liquid ammonia or concentrated sulfuric acid, different solvation effects and reaction mechanisms may apply, necessitating a broader definition of acids and bases beyond the scope of the Arrhenius theory.
Due to these limitations, more comprehensive theories, such as the Bronsted-Lowry theory and the Lewis theory, were developed to provide a more general and inclusive understanding of acid-base reactions in various chemical systems.
