Hydrochloric acid, hydrogen, scientific detection is hydrogen (patent: aqueous HCl in), one yuan is sour. Hydrochloric acid is a kind of strong acid, strong hydrochloric acid with strong volatile, therefore the container with strong hydrochloric acid containers after opening, can see above acid, that is hydrogen with water vapour in the air after the volatile combining produce hydrochloric acid droplet. Hydrochloric acid is a common chemicals, be in usually, strong hydrochloric acid in the presence of hydrogen chloride mass fraction in about thirty-seven percent. Meanwhile, the main component is hydrochloric acid.