HCl is a strong acid. A strong acid is defined as an acid that dissociates the ions when it is mixed with water. If the ions do not dissociate when mixed with water, it is considered a weak acid.
There are six strong acids. The first is HCl, which is short for hydrochloric acid. The other five are nitric acid, sulfuric acid, hydrobromic acid, hydroiodic acid and perchloric acid.
Hydrochloric acid is a solution of hydrogen chloride in water. It is corrosive, and it is clear and colorless in appearance. Hydrogen chloride molecules contain one hydrogen atom and one atom of chloride.