Hydrochloric acid, abbreviation HCl(aq), is a common acid both in the body and in the lab. It is, for example, a major component of gastric acid (pH 1-2, 0.5% w/v HCl). In experiments, it is used among other things to set the pH in buffers (e.g. Tris) and to reveal antigens (e.g. BrdU). Chemically speaking, it is a solution of the gas hydrogen chloride = HCl(g) in water.
- Concentrated HCl is a very strong acid that will burn your skin instantly upon contact! Wear gloves, goggles, and lab coat.
- Do not make the mistake of adding water to concentrated HCl. It has to acid into water. If you do it the wrong way the first drops of water mixing with the concentrated acid will heat up, evaporate, and can send drops of acid flying out of the container onto you.
- HClaq above 25% / 8M is corrosive
- HClaq above 10% / 3M is irritant