|Why do carbonated beverages "burn" your throat? — TS
When carbon dioxide gas (CO2) dissolves in water (H2O), its molecules often cling to water molecules in such a way that they form carbonic acid molecules (H2CO3). Carbonic acid is a weak acid, an acid in which most molecules are completely intact at any given moment. But some of those molecules are dissociated and exist as two dissolved fragments: a negatively charged HCO3- ion and a positively charged H+ ion. The H+ ions are responsible for acidity—the higher their concentration in a solution, the more acidic that solution is. The presence of carbonic acid in carbonated water makes that water acidic—the more carbonated, the more acidic. What you're feeling when you drink a carbonated beverage is the moderate acidity of that beverage "irritating" your throat.