Demonstration of the colours of the indicator phenolphthalein in first alkali (right) and then acid (left). The compound is pink in solutions with a pH above 10 (weak alkali), and colourless in solutions below pH 8.2 (weak alkali). It is also colourless above pH 13 (very strong alkali), but such levels are rarely encountered in such tests. | |
Licence : | Droits gérés |
Crédit : | Science Photo Library / RHYS LEWIS & MINH TAN PHAM, AHS, DECD, UNISA |
Model Release : | Non requis |
Durée : | 10 Secondes |
Aspect ratio : | 16/9 |
Restrictions : | - |