6-hydroxy-5-[[4-[[4-[(4-methylphenyl)amino]-3-sulphophenyl]azo]-1-naphthyl]azo]naphthalene-2-sulphonic acid, sodium salt

6-Hydroxy-5-[[4-[[4-[(4-methylphenyl)amino]-3-sulfophenyl]azo]naphthalene-1-yl]azo]-2-naphthalenesulfonic acid/sodium,(1:x) salt