2-Hydroxynaphthalene-7-sulfonic acid 2-Naphthalenesulfonic acid, 7-hydroxy- 2-Naphthol, 7-sulfo- 2-Naphthol-7-sulfonic acid 7-HYDROXYNAPHTHALENE-2-SULFONIC ACID 7-Hydroxy-2-naphthalenesulfonic acid 7-Hydroxynaphthalene-2-sulphonic acid 92-40-0 Cassella's acid EINECS 202-153-0 F Acid Mono Acid F Mono F Acid Monosulfonic acid F NSC 1704 beta-Naphthol-7-sulfonic acid