Which of the following reactions illustrates the formation of an oxyacid?

• A. CO₂ + H₂O → H₂CO₃
• B. H₂ + O₂ → H₂O
• C. N₂ + 3 H₂ → 2 NH₃
• D. HCl + NaOH → NaCl + H₂O

Answer: (A)