| IUPAC name
| Other names
Acid of air
Carbon dioxide solution
|Molar mass||62.03 g/mol|
|Appearance|| White solid (pure compound)|
Unstable liquid (aq. solution)
|Only stable in solution|
|Solubility|| Soluble in glycerol|
Insoluble in ethanol
|Acidity (pKa)|| 3.6 (pKa1 for H2CO3 only)|
6.3 (pKa1 including CO2(aq))
|Safety data sheet||FisherScientific (aq. sol.)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Carbonic acid is a very unstable, weak acid formed in small concentrations with dissolution of its anhydride, carbon dioxide, in water. Any solution containing it also contains molecular carbon dioxide dissolved in water.
Anhydrous carbonic acid cannot be isolated under normal conditions. Only in extreme conditions it becomes stable and isolable. Solutions of carbonic acid typically resemble soda water or mineral water (and usually are soda water or mineral water).
Carbonic acid is a weak diprotic acid. Its first dissociation gives H+ and the hydrocarbonate anion, HCO3-. The second dissociation gives another H+ and the carbonate anion, CO32-.
Solutions of carbonic acid and carbon dioxide react with alkaline bases, forming carbonate salts.
Sources and production
Solutions of carbon dioxide containing carbonic acid are sold as carbonated water.
- Make calcium bicarbonate
Solutions of carbonic acid are absolutely safe. They can be consumed by humans with no ill effects, providing no other chemicals are present in the solution. They are well known for the peculiar taste and refreshing effect provided by bubbles of carbon dioxide.
Solutions of carbonic acid can be stored in closed plastic bottles. You know, the same way you store soda. Because they are soda.
Carbonic acid does not require any special disposal and can be poured down the drain.