In the classical naming system, acids are named according to their anions. That ionic suffix is dropped and replaced with a new suffix (and sometimes prefix), according to the table below. For example, HCl has chloride as its anion, so the -ide suffix makes it take the form hydrochloric acid. In the IUPAC naming system, "aqueous" is simply added to the name of the ionic compound. Thus, for hydrogen chloride, the IUPAC name would be aqueous hydrogen chloride. The prefix "hydro-" is added only if the acid is made up of just hydrogen and one other element.
Classical naming system:
| Anion prefix | Anion suffix | Acid prefix | Acid suffix | Example |
|---|---|---|---|---|
| per | ate | per | ic acid | perchloric acid (HClO4) |
| ate | ic acid | chloric acid (HClO3) | ||
| ite | ous acid | chlorous acid (HClO2) | ||
| hypo | ite | hypo | ous acid | hypochlorous acid (HClO) |
| ide | hydro | ic acid | hydrochloric acid (HCl) |
