The formula for the conjugate acid of HSO4– is H2SO4.
When we talk about conjugate acids and bases in chemistry, we refer to pairs of compounds that differ by the presence or absence of a proton (H+ ion). HSO4–, known as the hydrogen sulfate ion, can accept a proton to form its conjugate acid. In this case, when HSO4– gains a proton (H+), it transforms into H2SO4, which is sulfuric acid. This relationship is crucial in understanding acid-base reactions and the behavior of different species in aqueous solutions.