Properties of Several Indicators
  Name HIn Color In- Color pH Range
A Thymol blue* red yellow 1.2 - 2.8
B Methyl orange red yellow 3.1 - 4.4
C Methyl red red yellow 4.2 - 6.3
D Bromthymol blue yellow blue 6.2 - 7.6
E Phenol red yellow red 6.8 - 8.2
F Thymol blue* yellow blue 8.0 - 9.6
* Thymol blue is a diprotic weak acid and has two color changes.