Which acid is produced when carbon dioxide dissolves in water?

Which acid is produced when carbon dioxide dissolves in water?

• A. Hydrochloric acid
• B. Carbonic acid (H2CO3)
• C. Nitric acid
• D. Acetic acid

Answer: (B)

When carbon dioxide dissolves in water, it forms a weak acid called carbonic acid. This happens because some of the CO2 reacts with water to make H2CO3: CO2 + H2O ⇌ H2CO3. Carbonic acid can donate protons, though not very strongly, so the solution becomes mildly acidic. It can further dissociate to form bicarbonate (HCO3−) and a second proton, and under certain conditions even carbonate (CO3^2−). This weak, diprotic acid explains the slight acidity of carbonated beverages. The other acids listed are not produced just by dissolving CO2 in water; they come from different substances with different properties.

When carbon dioxide dissolves in water, it forms a weak acid called carbonic acid. This happens because some of the CO2 reacts with water to make H2CO3: CO2 + H2O ⇌ H2CO3. Carbonic acid can donate protons, though not very strongly, so the solution becomes mildly acidic. It can further dissociate to form bicarbonate (HCO3−) and a second proton, and under certain conditions even carbonate (CO3^2−). This weak, diprotic acid explains the slight acidity of carbonated beverages. The other acids listed are not produced just by dissolving CO2 in water; they come from different substances with different properties.