4-[[5-[(5-chloro-2-hydroxyphenyl)azo]-2,4-dihydroxyphenyl]azo]naphthalene-1-sulphonic acid, sodium salt

4-[[5-[(5-Chloro-2-hydroxyphenyl)azo]-2,4-dihydroxyphenyl]azo]-1-naphthalenesulfonic acid/sodium,(1:x) salt