18. bromothymol blue
Also known as: 3',3''-dibromothymolsulfonephtalein
Type: HIn + H2O In- + H3O+
pK: 7.30
Approximate pH range for color change: 6.0-7.6
Color of acid form: yellow
Color of base form: blue
19.
20.
21. Approximate pH range for color change: 3.0-5.0
Color of acid form: blue
Color of base form: red
22. Also known as: o-cresolsulfonephthalein
Approximate pH range for color change: 0.0-1.0
Color of acid form: red
Color of base form: yellow
26. Also known as: m-cresol purple, cresol purple, m-
cresolsulfonephthalein
pK: ~2.0
Approximate pH range for color change: 1.2-2.8
Color of acid form: red
27. Approximate pH range for color change: 0.2-1.8
Color of acid form: yellow
Color of base form: blue
28. methyl orange
Type: InH+ + H2O In + H3O+
pK: 3.46
Approximate pH range for color change: 3.1-4.4
Color of acid form: red
Color of base form: orange-yellow
29. phenolphthalein
Type: HIn + H2O In- + H3O+
pK: 9.5
Approximate pH range for color change: 8.0-9.8
Color of acid form: clear
Color of base form: red-violet
