Pyrosulfuric

Pyrosulfuric acid, also known as disulfuric acid, is a chemical compound with the formula H2S2O7. It is the anhydride of sulfuric acid and is formed by the reaction of sulfur trioxide with sulfuric acid. Pyrosulfuric acid is a colorless, oily liquid that is highly corrosive and a strong oxidizing agent. It readily reacts with water to produce sulfuric acid. Its high acidity makes it useful in certain industrial applications, such as the production of explosives and dyes. It is also used in organic synthesis as a dehydrating agent and catalyst. Due to its hazardous nature, pyrosulfuric acid requires careful handling and storage. It is typically produced by bubbling sulfur trioxide gas through concentrated sulfuric acid. The concentration of sulfur trioxide in oleum, a fuming sulfuric acid, is an indicator of the amount of pyrosulfuric acid present. Pyrosulfuric acid can be distinguished from sulfuric acid by its greater reactivity and its tendency to fume in moist air due to the release of sulfur trioxide.