Auxiliary and Specific Data Tables

Properties of Aqueous Acid-Base Indicators at 25oC

James Richard Fromm


Indicator pH Range pKa Acid Form Base Form
Methy Violet 0.0 - 1.6 0.8 Yellow Blue
Thymol Blue 1.2 - 2.8 1.6 Red Yellow
Methyl Yellow 29. - 4.0 3.3 Red Yellow
Methyl Orange 3.1 - 4.4 4.2 Red Yellow
Bromocresol Green 3.8 - 5.4 4.7 Yellow Blue
Methyl Red 4.2 - 6.2 5.0 Red Yellow
Chlorophenol Red 4.8 - 6.4 6.0 Yellow Red
Bromothymol Blue 6.0 - 7.6 7.1 Yellow Blue
Phenol Red 6.4 - 8.0 7.4 Yellow Red
Cresol Purple 7.4 - 9.0 8.3 Yellow Purple
Thymol Blue 8.0 - 9.6 8.9 Yellow Blue
Phenolphthalein 8.0 - 9.8 9.7 Colorless Red
Thymolphthalein 9.3 - 10.5 9.9 Colorless Blue
Alizarin Yellow 10.1 - 12.0 11.0 Yellow Red
Indigo Carmine 11.4 - 13.0 12.2 Blue Yellow

Main Tables

Auxiliary Tables


Copyright 1997 James R. Fromm