Tetrathionic acid, also known as pyrosulfuric acid, is a chemical compound with various synonyms that can be used interchangeably. These synonyms include disulfurous acid, sulfuric acid anhydride, and disulfuric acid. Tetrathionic acid is a strong oxidizing agent and is commonly used in analytical chemistry, as well as in industrial processes. Its synonyms provide alternative terms to refer to this compound, allowing for a better understanding and communication in scientific literature and discussions. Regardless of the name used, tetrathionic acid plays a crucial role in various fields, demonstrating its versatility and importance in chemical applications.