Hydrolysis is a reaction that breaks a molecular bond using water. The reaction mainly occurs between ion and water molecules and often changes the pH of a solution. In chemistry, there are three main types of hydrolysis: salt hydrolysis, acid hydrolysis and base hydrolysis, according to UC Davis.
When placed in water, salts will either completely or incompletely dissociate depending on their respective solubility constant to form ions or completely new molecules. For example, if NaCl is placed in water, the reaction with water will cause the molecules to rearrange, creating the intermediate products of Na+, Cl-, H+ and OH-, explains UC Davis.
In acid hydroloysis, the water molecule in the hydrolysis can either accept or donate a proton depending on whether it is acting as a Bronsted-Lowry acid or base. When ethanoic acid is mixed with water, it gives an ethanoate ion and H3O+. The proton from acetic acid is donated to water, so water acts as a Bronsted-Lowry base in this example. Base hydrolysis resembles base dissociation. In the hydrolysis of a weak base, water acts as a Bronsted-Lowry acid and a hydroxide is formed as a byproduct of the reaction, states UC Davis.
In the real world, hydrolysis is an important process because most living things use metabolism to garner and store energy. During ATP biosynthesis, phosphate bonds have to be hydrolyzed in order for energy production to proceed and be catalyzed, according to Chemistry Explained. Additionally, to release the energy from an ATP molecule, hydrolysis breaks a phosphate group off an ATP molecule, states UC Davis.