...contains the sulfate anion (SO42−) and is called sulfuric acid; H3PO4<span> contains the phosphate anion (PO43−) and is called phosphoric acid; and HC2H3O2, which contains the acetate ion (C2H3O2−), is c... Phosphoric acid (</span>H3PO4<span>) has three hydrogen atoms, all of which are replaceable by a metal.</span>