Final answer:
The name for HPO4^2- is hydrogen phosphate, an amphoteric ion, meaning it can function as both an acid and a base in different reactions.
Step-by-step explanation:
The name for HPO42- is hydrogen phosphate. This ion can act as both an acid and a base, which makes it amphoteric. When HPO42- donates a proton, it forms H3O+ and PO43-, making it an acid. Conversely, when it accepts a proton from water, it forms H2PO4- and OH-, functioning as a base.
In naming conventions for oxyanions, when an ion has three oxygen atoms bound to a central phosphorus atom and one hydrogen atom with a negative two charge, it is called hydrogen phosphate. The pattern typically follows the root name of the anion with a prefix that indicates the number of hydrogens and a suffix that changes with the amount of oxygen present. For example, the phosphoric acid molecule, H3PO4, is the parent acid of hydrogen phosphate.
The systematic approach to naming oxyanions uses the suffix 'ate' when the ion contains more oxygen and 'ite' when it contains less. The 'hydrogen' prefix is used to indicate the presence of hydrogen, which partially neutralizes the charge. For example, H2PO4- is called dihydrogen phosphate.