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

Benzenesulfonic acid, 4-4,5-dihydro-4-(2-hydroxy-5-methyl-3-nitrophenyl)azo-3-methyl-5-oxo-1H-pyrazol-1-yl-, monosodium salt