Bicarbonation

Bicarbonation is a term used to describe the introduction or formation of bicarbonate ions (HCO3−) in a chemical system. It is not a single reaction but a category of processes in which bicarbonate becomes a predominant species in solution or a medium.

In aqueous chemistry, bicarbonate forms mainly through the dissolution of carbon dioxide in water, producing carbonic acid, which then dissociates into hydrogen ions and bicarbonate: CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3−. With increasing pH, bicarbonate can lose a proton to form carbonate (CO3^2−). The bicarbonate/carbonate system acts as a buffer over a wide pH range, with pKa values around 6.3 for the H2CO3/HCO3− pair and 10.3 for the HCO3−/CO3^2− pair at 25°C. In natural waters, bicarbonate is typically the dominant inorganic carbon species and helps stabilize pH.

In environmental and industrial contexts, bicarbonation often refers to adjusting or maintaining alkalinity by introducing bicarbonate species. This is relevant in water treatment to reduce corrosion, in aquaculture and soil systems to buffer pH, and in various chemical processes where buffering capacity is needed. In biological systems, bicarbonate is a key component of the physiological buffering system that helps maintain blood and cellular pH, although the term bicarbonation is less commonly used to describe clinical processes.

Industrially, sodium bicarbonate (baking soda) is a widely used source of bicarbonate for food, cleaning, medicine, and chemical synthesis. The concept of bicarbonation thus encompasses both natural carbonate chemistry and practical buffering applications across environmental, biological, and industrial settings.