1-Naphthalenesulfonic acid, 2-((2-hydroxy-1-naphthalenyl)azo)- 1-Naphthalenesulfonic acid, 2-((2-hydroxy-1-naphthalenyl)azo)-, sodium salt 12227-58-6 12237-76-2 2-((2-Hydroxy-1-naphthyl)azo)naphthalenesulphonic acid 29128-55-0 EINECS 249-459-0