Sulfuric acid dissociates in two distinct steps with different acid dissociation constants.

The claim states a basic chemical property of sulfuric acid: it is a diprotic acid whose first dissociation is strong and complete in dilute aqueous solution, while its second dissociation step occurs with a distinct acid dissociation constant (Ka2). This is a foundational, universally accepted fact taught in introductory chemistry and does not require citation of research papers. None of the retrieved papers are targeted at proving this basic definition from scratch, although paper [2] directly measures the second dissociation constant at various temperatures, treating the two-step nature as established chemical fact. Per instructions, trivially true or standard chemical definitions are classified as COMMON_KNOWLEDGE.