The name for the compound having the chemical formula H2CO3 is carbonic acid. It is formed from the reaction of carbon dioxide with water. Conversely, carbonic acid also disintegrates to produce carbon dioxide and water, which makes the reaction balanced, or in a state of equilibrium.
One of the components of normal air is carbon dioxide, which accounts for around 300 parts per million of air. When air mixes with water, the carbon dioxide reacts with the water molecules and dissolves to form carbonic acid. However, only a very small percentage of the gas is actually present in true carbonic acid and the rest is regarded as dissolved carbon dioxide.