Why is carbonic acid ($ ext{H}_2 ext{CO}_3$) classified as a weak acid in the context of beverage acidity?
It does not dissociate completely into hydrogen ions ($ ext{H}^+$) like a strong acid might.
Carbonic acid is fundamentally characterized as a weak acid because of its incomplete dissociation in solution. Unlike strong acids, which fully break apart into their constituent ions—primarily releasing hydrogen ions ($ ext{H}^+$) into the solution—carbonic acid remains largely molecular. This means that for any given concentration, it releases far fewer free hydrogen ions compared to a strong acid, resulting in a less drastic lowering of the overall $ ext{pH}$ of the liquid. While it still contributes to the mixture's acidity and provides the initial tart taste, its limited capacity to fully ionize prevents the $ ext{pH}$ from plummeting to the levels seen with potent substances like concentrated vinegar or stomach acid.
