5182-09-2 Benzenesulfonic acid, 3,3'-(4,5,6,7-tetrachloro-3-oxo-1(3H)-isobenzofuranylidene)bis(6-hydroxy-, disodium salt Chlorsulphalein Chlorsulphthalein Phenolphthalein, 4,5,6,7-tetrachloro-3',3''-disulfo-, disodium salt (7CI,8CI)