1-Naphthalenesulfonic acid, 3-hydroxy-4-((1-hydroxy-2-naphtalenyl)azo)- 1-Naphthalenesulfonic acid, 3-hydroxy-4-((1-hydroxy-2-naphthalenyl)azo)- 25747-05-1 3-Hydroxy-4-((1-hydroxy-2-naphthyl)azo)naphthalene-1-sulphonic acid EINECS 247-234-1