Synonyms: 2,7-Naphthalenedisulfonicacid, 4,5-dihydroxy-3-(p-nitrophenylazo)-, disodium salt (6CI);2,7-Naphthalenedisulfonic acid, 4,5-dihydroxy-3-[(4-nitrophenyl)azo]-, disodiumsalt (9CI);C.I. Acid Red 176 (7CI);C.I. Acid Red 176, disodium salt (8CI);4,5-Dihydroxynaphthalene-3-(4-nitrophenylazo)-2,7-disulfonic acid disodiumsalt;C.I. 16575;C.I. Mordant Black 93;Chromotrope 2B;Chromotrope Red 4B;Cr-2B;Naphtocard Fast Red 3B;PCR 2B;Poly-chromotrope 2B;p-Nitrobenzeneazochromotropic acid sodium salt;