Hydriodic acid is a chemical compound and the aqueous solution of hydrogen iodide or HI. It is formed when hydrogen iodide, a colorless gas, is dissolved in water. Usually pale yellow to muddy brown in color, it contains 48-51% of hydrogen iodide by mass. Most commonly used as a strong reducing agent because of its reducing ability and acidity, it is usually used in the production of acetic acid. Although acetic acid is toxic to human in its concentrated form, it is the basic chemical used to produce vinegar.
Hydriodic acid is a highly corrosive acid that has the ability to lose a proton, or take it back during a chemical reaction. This property in the acid means that it has many uses in chemical-based applications. With its high level of acidity, it kills many types of germs and viruses and is often used to as a means to sanitize and disinfect medical tools and products.