Its hydrochloric acid (H Cl) with the pH value of 1.
- Stomach acid is hydrochloric acid at a pH of 1, which means that it is at a concentration of 0.1 moles/liter.
- When something is swallowed, it reaches the stomach within seconds.
- Stomach acid does not dissolve enteric coatings. That's the whole point of an enteric coating; it doesn't break down until the small intestine. In fact, there's a really interesting picture in a recent New England Journal of Medicine of an enteric-coated aspirin lodged in a stomach ulcer. The coating was perfectly intact, so that you could still read the printing on it.
