carbonic acid

Noun

carbonic acid (uncountable)

1. A weak unstable acid, H₂CO₃, known only in solution, and as carbonate salts; it is present in carbonated drinks, and sparkling wine, but decomposes to form carbon dioxide and water.
   • Had she lived now, she would have talked of the last delightful lecture on gas, or the charming new treatise on carbonic acid; she would have studied German, and delighted in the society of "talented people."1837, L[etitia] E[lizabeth] L[andon], Ethel Churchill: Or, The Two Brides. […], volume II, London: Henry Colburn, […], →OCLC, pages 110–111
   • [I]t sank down through the air and poured over the ground in a manner rather liquid than gaseous, abandoning the hills, and streaming into the valleys and ditches and water-courses even as I have heard the carbonic acid gas that pours from volcanic clefts is wont to do.1898, H.G. Wells, The War of the Worlds, London: William Heinemann, page 144

   Synonyms:

   H₂CO₃

2. (obsolete) Carbon dioxide.