carbonic acid

American

noun

the acid, H 2 CO 3 , formed when carbon dioxide dissolves in water, known in the form of its salts and esters, the carbonates.

carbonic acid British

noun

a weak acid formed when carbon dioxide combines with water: obtained only in aqueous solutions, never in the pure state. Formula: H 2 CO 3

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

carbonic acid Scientific

/ kär-bŏn′ĭk /

A weak, unstable acid present in solutions of carbon dioxide in water. It gives carbonated beverages their sharp taste. Chemical formula: H ₂ CO ₃ .

Etymology

Origin of carbonic acid

First recorded in 1785–95

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

carbonic acid

When exposed to air, the potassium hydroxide inside the beads reacts with CO2, producing hydrogen carbonate, a salt of carbonic acid.

From Science Daily ● Jun. 11, 2026

That weak carbonic acid ultimately soaks into the soil, full of carbon dioxide.

From Slate ● Oct. 17, 2025

This happens because carbon dioxide from the air dissolves in rainwater to form carbonic acid - this then percolates through the rock and reacts with it, causing it to dissolve.

From BBC ● Feb. 19, 2025

The carbon dioxide, buffered into carbonic acid, increases acidity in ocean water, which is bad news for corals, clams and other shell-forming creatures.

From Los Angeles Times ● Jun. 5, 2024

Other organisms form carbon dioxide, which, as carbonic acid, aids in dissolving rock.

From "Silent Spring" by Rachel Carson

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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023