PH Indicators

Updated 2009-02-04 22:06

pH Indicators

Indicator NameLower pH and ColorUpper pH and Color
Malachite green oxalate0.0 green2.0 green-blue
Brilliant green0.0 yellow2.6 green
Eosin yellowish0.0 yellow3.0 green fluoresc.
Erythrosine B0.0 yellow3.6 red
Methyl green0.1 yellow2.3 blue
Methyl violet0.1 yellow2.7 violet
Picric acid0.2 colourless1.0 yellow
Cresol red0.2 red1.8 yellow
Crystal violet0.8 yellow2.6 blue/violet
m-Cresol purple1.2 red2.8 yellow
Thymol blue1.2 red2.8 yellow
p-Xylenol blue1.2 red2.8 yellow
Eosin, bluish1.4 colourless2.4 pink fluoresc.
Quinaldine red1.4 colourless3.2 pink
2,4-Dinitro phenol2.8 colourless4.7 yellow
4-(Dimethylamino) azobenzol2.9 red4.0 yellow/orange


Indicator NameLower pH and ColorUpper pH and Color
Bromochlorophenol blue3.0 yellow4.6 blue/violet
Bromophenol blue3.0 yellow4.6 blue/violet
Congo red3.0 blue5.2 yellow/orange
Methyl orange3.1 red4.4 yellow/orange
Bromocresol green3.8 yellow5.4 blue
2,5-Dinitrophenol4.0 colourless5.8 yellow
Alizarin sulphonic acid4.3 yellow6.3 violet
Methyl red4.4 red6.2 yellow/orange
Chlorophenol red4.8 yellow6.4 purple
Litmus5.0 red8.0 blue
Bromocresol purple5.2 yellow6.8 purple
Bromophenol red5.2 orange/yellow6.8 purple
4-Nitrophenol5.4 colourless7.5 yellow
Bromoxylenol blue5.7 yellow7.5 blue
Bromothymol blue6.0 yellow7.6 blue
Phenol red6.4 yellow8.2 red/violet
3-Nitrophenol6.6 colourless8.6 yellow/orange
Neutral red6.8 blue/red8.0 orange/yellow


Indicator NameLower pH and ColorUpper pH and Color
Creosol red7.0 orange8.8 purple
1-Naphtholphthalein7.1 brownish8.3 blue/green
m-Cresol purple7.4 yellow9.0 purple
Thymol blue8.0 yellow9.6 blue
p-Xylenol blue8.0 yellow9.6 blue
Phenolphthalein8.2 colourless9.8 red/violet
Alizarin(1)8.6 yellow11.4 red
Thymolphthalein9.3 colourless10.5 blue
Alkali blue9.4 violet14.0 pink
Alizarin yellow GG10.0 bright yellow12.1 brown/yellow
Indigo carmine11.5 blue13.0 yellow
Epsilon blue11.6 orange13.0 violet
Sodium indigo sulfonate(1)11.7 blue13.9 yellow
Titan yellow12.0 yellow13.0 red


References: for most.
p.647 of "Chemistry" by Steven S. Zumdahl, D.C. Heath and Company, 1986 for (1)'s.