The ion known as bisulfite is represented as HSO3-. This ion is characterized by the presence of a sulfur atom bonded to three oxygen atoms, with one oxygen carrying a hydrogen atom, thus giving it its bisulfite designation. The "bisulfite" nomenclature indicates that it has one less oxygen than its corresponding sulfate ion (SO4^2-), leading to the formula HSO3-. This ion can also act as a reducing agent and is often encountered in various chemical contexts, particularly in acid-base reactions.
In contrast, the sulfate ion (SO4^2-) has no hydrogen and carries a -2 charge, while the sulfite ion (SO3^2-) contains the same number of oxygen atoms as bisulfite but without the additional hydrogen. The cyanide ion (CN-) does not relate to sulfur or its oxides, making it irrelevant to the question. Thus, identifying HSO3- as bisulfite is accurate based on its structure and chemical properties.