α-Naphtholphthalein (C28H18O4) is a phthalein dye used as a pH indicator with a visual transition from colorless/reddish to greenish blue at pH 7.3–8.7.
| Naphtholphthalein (pH indicator) | ||
| below pH 7.3 | above pH 8.7 | |
| 7.3 | ⇌ | 8.7 |
References
- ^ a b c d α-Naphtholphthalein