H2CO3, known as carbonic acid, is a weak acid formed when carbon dioxide (CO2) dissolves in water. It plays a crucial role in maintaining the pH balance in natural waters and biological systems. Carbonic acid can dissociate into bicarbonate (HCO3-) and hydrogen ions (H+), which are important for various chemical processes. In the human body, carbonic acid is involved in the regulation of blood pH and is part of the bicarbonate buffer system. This system helps to maintain stable pH levels in the blood, which is essential for proper physiological function. Carbonic acid is also present in carbonated beverages, contributing to their fizz.