Carbonic acid

Carbonic acid (CAS 463-79-6) is a weak inorganic acid formed when carbon dioxide dissolves in water, existing in equilibrium with dissolved CO2 in aqueous systems. In industrial and commercial contexts, it functions primarily as a pH-regulating agent and mild acidulant across water treatment, food processing, and pharmaceutical applications.

In municipal and industrial water treatment, it is used to adjust alkalinity and control scaling in distribution systems without introducing chloride or sulfate ions. Carbonated beverage production relies on dissolved CO2/carbonic acid equilibrium to deliver consistent acidity and preservation in soft drinks, sparkling water, and beer.

In pharmaceutical manufacturing, buffered carbonic acid systems support pH stabilization in parenteral formulations and effervescent tablet chemistry for various products. Agricultural irrigation systems use carbonic acid dosing to lower the pH of alkaline water, improving nutrient availability and preventing mineral deposits in drip lines.

Carbonic acid is not isolable as a stable pure compound and is supplied commercially as CO2 gas or carbonated aqueous solutions for direct application in many industries. Food-grade and technical-grade CO2 are the standard supply forms, with food-grade material meeting specifications under FCC and relevant pharmacopeial standards.