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Why did Arrhenius' theory have to be modified?

a) It failed to explain the behavior of non-aqueous solutions.
b) It contradicted the principles of chemical equilibrium.
c) It lacked experimental evidence.
d) It disregarded the concept of ionization.

User Eternal
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Final answer:

Arrhenius' theory was modified because it only explained acid-base reactions in aqueous solutions and could not account for reactions in non-aqueous solvents or explain the behavior of certain weak bases like ammonia.

Step-by-step explanation:

The Arrhenius theory had to be modified because it failed to explain the behavior of non-aqueous solutions. Specifically, the Arrhenius theory defined acids as substances that increase the concentration of H+ ions in aqueous solutions and bases as substances that increase the concentration of OH- ions.

This definition was limited to aqueous (water) solutions and could not account for acid-base behavior in non-aqueous solvents, such as benzene.

Furthermore, Arrhenius' theory did not explain the acid-base properties of substances that do not release H+ or OH- ions in water, such as ammonia (NH3), which acts as a weak base by releasing hydroxide ions in the presence of water despite not containing OH- itself.

The limitation of the Arrhenius concept to aqueous solutions and its inability to describe the behavior of all acids and bases necessitated the development of new theories, including the Brønsted-Lowry theory, which expanded the definition of acids and bases beyond the presence of aqueous H+ and OH- ions.

User Bakuriu
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