Final answer:
A diprotic acid, such as H2CO3 (carbonic acid), undergoes stepwise ionization in two steps. The first ionization produces hydronium ions and bicarbonate ions in small amounts, while the second ionization occurs to an even lesser extent. This stepwise ionization process is common to all polyprotic acids.
Step-by-step explanation:
Diprotic acids contain two ionizable hydrogen atoms per molecule, and their ionization occurs in two steps. One example of a diprotic acid is carbonic acid (H2CO3). The first ionization of carbonic acid produces hydronium ions (H3O+) and bicarbonate ions (HCO3-) in small amounts. The second ionization occurs to an even lesser extent. The stepwise ionization process of a diprotic acid is a common characteristic of all polyprotic acids.