Indicators

pH range
Color change Indicator name pKa
0.2-1.8 yellow to blue/green Malachite Green 1.30
0.2-1.8yellow to blueMethyl Green 
1.2-2.4red to yellowMetanil Yellow 
1.2-2.8 red to yellow Metacresol Purple 1.51
1.2-2.8 red to yellow Thymol Blue 1.65
1.4-2.8red to yellow Orange IV 
1.4-3.2 colorless to red Quinaldine Red 2.63
3.2-4.4 red to yellow Methyl Orange 3.46
3.0-4.6 yellow to blue Bromophenol Blue 4.10
3.4-4.8 red to yellow Ethyl Orange 4.34
3.8-5.4 yellow to blue Bromocresol Green 4.90
4.8-6.0 red to yellow Methyl Red 5.00
4.0-5.8 colorless to red Ethyl Red 5.42
4.8-6.6 red to yellow Propyl Red
5.48
5.2-6.8 yellow to red Chlorophenol Red
6.25
5.2-6.8 yellow to purple Bromocresol Purple
6.40
5.4-6.6 colorless to yellow p-Nitrophenol 7.15
5.6-7.2 yellow to redAlizarin  
6.0-7.6 yellow to blue Bromothymol Blue 7.30
6.6-7.8yellow to red Brilliant Yellow 
6.6-8.0 yellow to red Phenol Red 8.00
6.8-8.6 colorless to yellow m-Nitrophenol 8.28
7.4-9.0 yellow to purple Metacresol Purple 8.30
7.0-8.8 yellow to red Cresol Red 8.46
8.0-9.6 yellow to blue Thymol Blue 9.20
8.2-9.8colorless to red  o-Cresolphthalein 
8.2-10.0 colorless to pink Phenolphthalein 9.50
9.4-10.6colorless to blueThymolphthalein 
10.1-12.0yellow to red Alizarin Yellow R  
11.2-13.0colorless to orange 2,4,6-Trinitrotoluene 
12.0-14.0colorless to orange1,3,5-Trinitrobenzene 
12.2-13.2yellow to amberClayton Yellow 

Reference: CRC Handbook of Chemistry and Physics, 2007
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