Also Called: 2-Naphthalenesulfonic acid, 6-amino-5-[[2-[(ethylphenylamino) sulfonyl]phenyl]azo]-4-hydroxy-, monosodium salt;2-Naphthalenesulfonic acid, 6-amino-5-[[2-[(ethylphenylamino)sulfonyl]phenyl]azo]-4-hydroxy-, monosodium salt;2-Naphthalenesulfonic acid, 6-amino-5-[2-[2-[(ethylphenylamino)sulfonyl]phenyl]diazenyl]-4-hydroxy-, sodium salt (1:1)