2,7-Naphthalenedisulfonic acid, 4,5-dihydroxy-3-((4-nitrophenyl)azo)-, disodium salt 548-80-1 C.I. 16575 C.I. Acid Red 176 (VAN) C.I. Acid Red 176, disodium salt (8CI) Chromatrope 2B Chromotrope 2B Chromotrope Red 4B Disodium 4,5-dihydroxy-3-(p-nitrophenylazo)naphthalene-2,7-disulphonate EINECS 208-959-9 Khromotrop 2B NSC 45542 Naphtocard Fast Red 3B p-Nitrobenzeneazochromotropic acid sodium salt