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Chromotropic acid disodium salt has the formula is (HO)2C10H4(SO3Na)2.2H2O.
C 2285 (OTTO) Chromotropic acid disodium salt, 98% Cas 5808-22-0 - used for as a reagent in the quantitative determination of the systemic herbicide, 2,4-Dichlorophenoxyacetic acid.