Hydrolysis is a reaction between organic compounds and water. It is characterized by the splitting of water molecules to form positively charged hydrogen (H+) and negatively charged hydroxide (-OH).
The most common type of hydrolysis occurs when a salt of a weak base, weak acid or both dissolves in water. Water ionizes into hydrogen cations and hydroxide anions. The salt also splits into its constituent cations and ions. For example, sodium acetate breaks down in water to form sodium and acetate ions. Sodium ions react very little with the hydroxide anions, whereas the acetate ions react with hydroxide ions to form a neutral acetic acid.
Strong acids and bases also undergo hydrolysis. For example, when concentrated sulfuric acid (H2SO4) is dissolved in water, it undergoes hydrolysis to form hydronium and bisulfate. Similarly, when concentrated sodium hydroxide dissolves in water, it dissociates to form sodium ions (Na+) and hydroxide ions (-OH).
Under normal conditions, only a few organic compounds react readily with water. This is because their molecules are less polar than the water molecules. For hydrolysis to take place, strong acids or bases must be added in order to speed up the reactions. These types of reactions are referred to as base-catalyzed or acid-catalyzed reactions. They are mostly used in important industrial processes, such as the manufacture of soap.