After you identified the unknown substance as hydrofluoric acid, the police contacted a local chemical supply company to see whether or not anyone had purchased hydrofluoric acid recently. When the company told the police that they do not sell hydrofluoric acid, the police asked whether or not anyone had purchased substances that might have been used to make hydrofluoric acid. In response, the company released information about three suspicious orders. Explain why knowing additional information about hydrofluoric acid and other substances might help solve this crime.