hüdrohalogeeni

A hydrohalogen, also known as a hydrogen halide, is a diatomic molecule with the formula HX, where H is hydrogen and X is a halogen atom. The halogens are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). Therefore, the common hydrohalogens are hydrogen fluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), and hydrogen iodide (HI). Hydrogen astatide (HAt) is also a hydrohalogen, but it is highly unstable and radioactive.

Hydrohalogens are typically gases at room temperature and pressure. They are all polar molecules due to the difference in electronegativity between hydrogen and the halogen. When dissolved in water, hydrohalogens form hydrohalic acids. For example, hydrogen chloride dissolves in water to form hydrochloric acid. These acids are strong acids, with the exception of hydrofluoric acid, which is considered a weak acid.

Hydrohalogens have various industrial and laboratory applications. Hydrogen chloride is used in the production of plastics, pharmaceuticals, and in metal pickling. Hydrogen fluoride is used in the production of refrigerants, aluminum, and in etching glass. Hydrogen bromide and hydrogen iodide are used as reagents in organic synthesis.

The reactivity of hydrohalogens varies. Hydrogen fluoride is the most reactive due to the high electronegativity of fluorine and the strength of the H-F bond. Hydrogen iodide is the least reactive, and its HI bond is the weakest. This decreasing reactivity down the group is a common trend in chemistry.