Page 60 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Acid-Base Theories

1. Arrhenius Theory

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➢ Acids are substances that produce hydrogen ions (H ) when dissolved in

water.

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➢ Free Hydrogen ions do not exist by themselves in solution. H is always

bound to a water molecule to form a hydronium ion.

Acids

➢ Bases are substances that produce hydroxide ions

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(OH ) when dissolved in water.

Bases

➢ A major problem with the Arrhenius Theory is that it limits acids and
bases to water (aqueous) solutions.
➢ Since an acid requires water to ionize and form hydronium ions, there
can be no Arrhenius acids unless water is involved as the solvent.
Note ➢ Also, it does not discuss the presence of substances that do not contain

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H and considered acids and presence of substances that do not contain
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OH and considered bases.

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