4-[(4-amino-5-methoxy-o-tolyl)azo]-5-[(phenylsulphonyl)oxy]naphthalene-2,7-disulphonic acid, sodium salt

4-[(4-Amino-5-methoxy-2-methylphenyl)azo]-5-[(phenylsulfonyl)oxy]-2,7-naphthalenedisulfonic acid/sodium,(1:x) salt