Question: how does the human body make hydrochloric acid?
Answer: HCl is produced by the parietal cells of the stomach. To begin with, water (H2O) and carbon dioxide (CO2) combine within the parietal cell cytoplasm to produce carbonic acid (H2CO3), catalysed by carbonic anhydrase. Carbonic acid then spontaneously dissociates into a hydrogen ion (H+) and a bicarbonate ion (HCO3–).