Sulfuric acid-d2 solution (D₂SO₄) is a deuterated analog of sulfuric acid, used as a reagent in isotopic labeling studies and acid-catalyzed reactions requiring deuterium incorporation. It facilitates the investigation of reaction mechanisms, kinetic isotope effects, and molecular dynamics in organic synthesis and biochemical research. In spectroscopy, such as NMR, it serves in specialized acidic environments for analyzing deuterated samples or reactions, rather than as a general solvent due to its high reactivity and corrosiveness. It is also applied in the production of deuterated pharmaceuticals and fine chemicals for advanced R&D, and in industrial processes involving selective deuteration.