What is a diprotic acid?

A diprotic acid is an acid that can donate two protons or hydrogen ions per molecule in an aqueous solution. This means that it has two dissociable hydrogen atoms that can ionize when the acid is dissolved in water.

Examples of diprotic acids include sulfuric acid (H2SO4), carbonic acid (H2CO3), and oxalic acid (H2C2O4).

When a diprotic acid dissociates in water, it undergoes two ionization reactions. The first ionization typically occurs more readily than the second, resulting in two dissociation constants, Ka1 and Ka2, which represent the equilibrium constants for the successive ionization reactions.

The pH of a solution of a diprotic acid will depend on the concentrations of the acid species present and the values of the dissociation constants. Diprotic acids are often involved in buffer solutions and are important in various industrial and biological processes.