ABSTRACT
Indicator pH Range Solvent Acid Base Gentian violet (crystal violet) 0.0-2.0 Aqueous Yellow Blue-violet Thymol blue 1.2-2.8 Aqueous Red Yellow Pentamethoxy red 1.2-2.3 70% ethanol Red-violet Colorless Tropeolin OO 1.3-3.2 Aqueous Red Yellow 2,4-dinitrophenol 2.4-4.0 50% ethanol Colorless Yellow Methyl yellow 2.9-4.0 90% ethanol Red Yellow Methyl orange 3.1-4.4 Aqueous Red Orange Bromophenol blue 3.0-4.6 Aqueous Yellow Blue-violet Tetrabromphenol blue, sodium salt 3.0-4.6 Aqueous Yellow Blue Congo red 3.0-5.0 Aqueous Blue-violet Red Alizarin sodium sulfonate 3.7-5.2 Aqueous Yellow Violet α-Naphthyl red 3.7-5.0 70% ethanol Red Yellow p-Ethoxychrysoidine 3.5-5.5 Aqueous Red Yellow Bromocresol green, sodium salt 4.0-5.6 Aqueous Yellow Blue Methyl red, sodium salt 4.4-6.2 Aqueous Red Yellow Bromocresol purple 5.2-6.8 Aqueous Yellow Purple Chlorphenol red 5.4-6.8 Aqueous Yellow Red Bromophenol blue, sodium salt 6.2-7.6 Aqueous Yellow Blue p-nitrophenol 5.0-7.0 Aqueous Colorless Yellow Azolitmin 5.0-8.0 Aqueous Red Blue Bromothymol blue, sodium salt 6.0-7.6 70% ethanol Yellow Blue Phenol red, sodium salt 6.4-8.0 Aqueous Yellow Red Neutral red 6.8-8.0 70% ethanol Red Yellow Rosolic acid 6.8-8.0 90% ethanol Yellow Red Cresol red, sodium salt 7.2-8.8 Aqueous Yellow Red α-naphtholphthalein 7.3-8.7 70% ethanol Rose Green Tropeolin OOO 7.6-8.9 Aqueous Yellow Rose-red Thymol blue, sodium salt 8.0-9.6 Aqueous Yellow Blue Phenolphthalein 8.0-10.0 70% ethanol Colorless Red α-naphtholbenzein 9.0-11.0 70% ethanol Yellow Blue Thymolphthalein 9.4-10.6 90% ethanol Colorless Blue Nile blue 10.1-11.1 Aqueous Blue Red Alizarin yellow R 10.0-12.0 Aqueous Yellow Lilac Salicyl yellow 10.0-12.0 90% ethanol Yellow Orange-brown Diazo violet 10.1-12.0 Aqueous Yellow Violet Tropeolin O 11.0-13.0 Aqueous Yellow Orange-brown Nitramine 11.0-13.0 70% ethanol Colorless Orange-brown Poirrier’s blue 11.0-13.0 Aqueous Blue Violet-pink Trinitrobenzoic acid 12.0-13.4 Aqueous Colorless Orange-red
