Applications
Most hydrogen chloride is used in the production of hydrochloric acid. It is also an important reagent in other industrial chemical transformations, e.g.:
- Hydrochlorination of rubber
- Production of vinyl and alkyl chlorides
In the semiconductor industry, it is used to both etch semiconductor crystals and to purify silicon via trichlorosilane (SiHCl3).
It may also be used to treat cotton to delint it, and to separate it from wool.
In the laboratory, anhydrous forms of the gas are particularly useful for generating chloride-based Lewis acids, which must be absolutely dry for their Lewis sites to function. It can also be used to dry the corresponding hydrated forms of these materials by passing it over as they are heated; the materials would otherwise fume HCl(g) themselves and decompose. Neither can these hydrates be dried using standard desiccator methods.
Read more about this topic: Hydrogen Chloride