Final answer:
Citric acid is tripotic because it contains three carboxyl groups that can each donate a hydrogen ion, unlike monoprotic acetic acid, which has only one such group. It plays a vital role in the Krebs cycle, highlighting its importance in metabolism and industrial applications.
Step-by-step explanation:
Citric acid (C6H8O7) is considered triprotic because it contains three carboxyl groups (-COOH), each of which can donate a hydrogen ion (H+) when the acid is dissolved in water. This means it has the potential to donate three protons, which is characterized by its three ionizable hydrogen atoms. Hence, citric acid can undergo three successive reactions with bases, each time losing a proton.
In contrast, acetic acid (CH3CO2H or CH2CO2H) is monoprotic because it contains only one carboxyl group that can donate a hydrogen ion. Although it has four hydrogen atoms, only the hydrogen from the carboxyl group is reactive with bases.
Citric acid is an important metabolite in the Krebs cycle (TCA cycle), which is a series of chemical reactions used by all aerobic organisms to release stored energy through the oxidation of acetyl-CoA. Given its role in metabolism and its three ionizable hydrogen atoms, citric acid's properties significantly contribute to its function both within organisms and in various industrial applications, such as food preservation and flavoring, especially in soft drinks.