Product Code: 1.1350
Neutronco
Phenolphetalein
Formula
Molar Mass
CAS Number
HS Code
Uses
| Formula: | C20H14O4 |
| Density: | 1.30 g/cm3 (20 °C) |
| Molar mass: | 318.33 g/mol |
| Bulk density: | 350 450 kg/m3 |
| CAS number: | 77-09-8 |
| HS code: | 29322910 |
| EC number: | 201-004-7 |
| Storage : | Without limitations |
| SDS | available |
| Description | Conforms | °C | |
| Identification | Conforms | nm | |
| Melting Point | 285.0 – 262.0 | % | |
| Clarity of alcoholic solution | Conforms | ||
| Absorption maximum | 551.0 –554.0 | ||
| Transition Range | Conforms | ||
| Loss on drying | ≤ | 1 |
Phenolphthalein is an organic compound used as a pH indicator in acid–base titrations. It is colorless in acidic solutions and turns pink to fuchsia in basic solutions. It belongs to the phthalein dye family.
🔬 Properties
Phenolphthalein is a weak acid. Its colorless, non-ionized form becomes pink in basic environments due to double deprotonation. At very high pH, it may turn colorless again as its conjugated system breaks down.
It is slightly water-soluble and usually dissolved in alcohol for lab use. In concentrated sulfuric acid, it appears orange-red due to protonation and formation of a stabilized cation.
🏭⚗️ Synthesis
It is synthesized by condensing phthalic anhydride with phenol under acidic conditions. Discovered by Adolf von Baeyer in 1871.
🧪 Applications
• pH Indicator: Widely used in acid–base titrations.
• Concrete Testing: Detects carbonation—pink in alkaline areas, colorless in carbonated zones.
• Spackling Products: Turns colorless as drywall filler reacts with air.
• Educational Use: Demonstrates reaction kinetics and pH-dependent color changes.
