Orthophosphorous acid is a compound also known as phosphonic acid or hydrogen phosphite. Other synonyms for this acid include monophosphorous acid, phosphinic acid, and orthophosphonic acid. These different names refer to the same chemical, with varying degrees of specificity in their nomenclature. Orthophosphorous acid is a type of phosphorus-based acid that is commonly used as a chelating agent in industrial applications or as a disinfectant in water treatment processes. Its ability to sequester metals and inhibit scale formation makes it an important ingredient in many manufacturing processes. Understanding the different synonyms for orthophosphorous acid is essential for scientists and engineers to communicate effectively in their respective fields.