Chemical indicators
What is a chemical indicator?
A chemical indicator is a substance that changes color in the presence of an acid and an alkali
Acids taste sour and bases taste bitter. Many acids and bases however, cannot be tasted as they are corrosive.
Chemical indicators are a safer way to determine if a chemical substance is acidic or basic.
| Chemical indicator | Color in acid | Color in base |
| Litmus paper | Pink | Blue |
| Phenolphthalein | Colorless | Pink/ violet |
| Bromothymol blue | Yellow | Blue |
Chemical indicators are commonly used to test the acidic. basic nature of soils.
They are also used to test the acidic basic conditions of water in swimming pools and fish tanks.