sodium 4-[4-[(2-chlorophenyl)azo]-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulphonate

4-[4-(2-Chlorophenylazo)-4,5-dihydro-3-methyl-5-oxo-1H-pyrazol-1-yl]benzenesulfonic acid sodium salt