2-Pyrazolin-5-one, 4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-1-(p-sulfophenyl)-, sodium salt 6359-86-0 Benzenesulfonic acid, 4-(4,5-dihydro-4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-5-oxo-1H-pyrazol-1-yl)-, monosodium salt EINECS 228-811-7 Sodium p-(4,5-dihydro-4-((2-hydroxy-5-nitrophenyl)azo)-3-methyl-5-oxo-1H-pyrazol-1-yl)benzenesulphonate