What is Phenolphthalein?
Phenolphthalein is a member of phenols and is functionally related to a 2-benzofuran-1(3H)-one. It is a chemical compound commonly used as a pH indicator in various applications. It is colorless in acidic solutions (below pH 8.3) and turns pink or magenta in alkaline/basic solutions (above pH 10). This characteristic color change makes it valuable in determining the acidity or alkalinity (pH) of a solution, particularly in laboratory settings, educational demonstrations, and various industrial processes.
Macsen Laboratories is the leading manufacturer and supplier of Phenolphthalein with ISO certification.
| PRODUCT SPECIFICATIONS | |
|---|---|
| Name of Product | Phenolphthalein |
| IUPAC Name | 3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one |
| Synonyms | Phthalimetten; Euchessina; Phthalin; Espotabs; Phenolax; Purgophen; Koprol; Laxogen; Fenolftaleina; fenolftaleÃna |
| CAS No | 77-09-8 |
| Molecular Formula | C20H14O4 |
| Molecular Weight | 318.3 g/mol |
| Pubchem CID | 4764 |
CHEMICAL PROPERTIES
| SR. No | Criteria | Limit/Specification |
|---|---|---|
| 1 | Appearance (Form) | Solid Powder |
| 2 | Appearance (Color) | White to Off-white |
| 3 | pH range (8.2 - 10.0) | Colorless to Red-violet |
| 4 | Absorption maxima (buffer pH 9.8) | 551 - 554 nm |
| 5 | Sulphated Ash | NMT 0.05% |
| 6 | Chloride (Cl) | NMT 0.01% |
| 7 | Sulphate (SO4) | NMT 0.01% |
| 8 | Loss on drying (at 110°C) | NMT 1% |
Uses
- Phenolphthalein is widely used in chemical laboratories to determine the pH of a solution during acid-base titrations and other experiments. Additionally, it functions as a constituent of universal indicator when used together with thymol blue, bromothymol blue, and methyl red.
- It can be used to test the pH of water in swimming pools, aquariums, and other water treatment applications to ensure water quality and safety.
- Phenolphthalein finds application in toy manufacturing, such as in disappearing ink components and disappearing pigments utilized in the creation of “Hollywood Hair” Barbie hair.
- It is used in the carbonation of concrete.
- Phenolphthalein, in its colorless reduced form, is employed in the Kastle–Meyer test, which is a physiological procedure utilized to detect substances suspected of containing blood.
- It is also used in educational settings for chemistry demonstrations and engaging experiments, showcasing the concept of pH changes.
- Additionally, it has been used as a laxative in the past, but it has now largely been replaced by safer alternatives due to concerns about its safety.
FAQs
Q. What color is phenolphthalein when the solution is acidic ?
Phenolphthalein is colorless in acidic solutions.
Q. What is the pKa of phenolphthalein?
Phenolphthalein has a pKa value of 9.7.
Q. Is phenolphthalein an acid?
Phenolphthalein is a weak acid.
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