Answer – The strongest acid in the world is fluoroantimonic acid, HSbF6. It is prepared by mixing antimony pentafluoride (SbF₅) with hydrogen fluoride (HF).
Explanation:
HSbF6 is a superacid, which means it is stronger than pure sulfuric acid.
Due to its strength, the acidity of HSbF6 cannot be measured with a pKₐ value; instead, it is measured using the Hammett acidity function, represented by H₀. Superacids like HSbF6 give up a great number of hydrogen ions in water and hence have H₀ values lower than –12.
Fluoroantimonic acid’s H₀ value is –31.3. This acid is 2×10¹⁹ times stronger than sulfuric acid, making it so corrosive that it cannot be stored in glass containers. It is instead stored in polytetrafluoroethylene containers. At high temperatures, HSbF6 breaks down to produce poisonous vapors of HF (hydrogen fluoride) gas. It also reacts with water explosively and thus must always be used in hydrofluoric acid solution.
Despite its extreme toxicity, fluoroantimonic acid is used extensively in organic chemistry and chemical engineering. It is employed for improving gasoline quality, manufacturing grenades, and etching glass.
