Indicators are used in titration solutions to signal the completion of the acid-base reaction. Did you know that the indicators are generally clear, but as the solution of known concentration is added using a burette, the solution in question will change colors? Different indicators are used for different pH ranges. Take a moment to view the table that contains several different commonly use indicators.
Indicator |
End Point Color in the Presence of Acid |
End Point Color in the Presence of Base |
pH Range |
---|---|---|---|
Thymol Blue | Red | Yellow | 1.2-1.8 |
Methyl Orange | Red | Yellow | 3.2-4.4 |
Bromocresol Green | Yellow | Blue | 3.8-5.4 |
Methyl Red | Yellow | Red | 4.8-6.0 |
Bromothymol Blue | Yellow | Red | 6.8-8.4 |
Thymol Blye | Yellow | Blue | 8.0-9.6 |
Phenolphtalein | Colorless | Pink | 8.2-10.0 |