Iodwasserstoffsäure

Iodwasserstoffsäure is the German name for hydroiodic acid. It is a strong acid with the chemical formula HI. Hydroiodic acid is a colorless liquid at room temperature and pressure, though it is typically sold as an aqueous solution. It is one of the six common strong acids in chemistry.

The acid is formed when hydrogen iodide gas dissolves in water. Hydrogen iodide itself is a highly reactive gas. Hydroiodic acid is a potent reducing agent due to the ease with which the iodide ion (I⁻) can be oxidized to iodine (I₂). This reducing property makes it useful in various chemical reactions.

Hydroiodic acid is used in organic chemistry to produce alkyl iodides, which are common intermediates in synthesis. It can also be used to reduce alcohols to alkanes. In analytical chemistry, it is employed in titration experiments. Due to its corrosive nature and strong reducing properties, it must be handled with care, wearing appropriate personal protective equipment. Solutions of hydroiodic acid can turn yellow or brown over time as they oxidize in the presence of air, forming iodine.