When a 1% phenolphthalein solution is applied to normal concrete, it turns bright pink. This has raised suspicions over the use of phenolphthalein by humans.

Phenolphthalein is just an indicator. 3.

Articles from Britannica Encyclopedias for elementary and high school students. Phenolphthalein was widely used as a laxative for over a century. Let us know if you have suggestions to improve this article (requires login). In a highly basic solution, phenolphthalein's slow change from pink to colorless as it is converted to its In(OH)3− form is used in chemistry classes for the study of reaction kinetics. The UC review of "Alkali-Aggregate Reaction in Concrete: A World Review" edited by Iam Sims and Alan Poole. However, if it remains colorless, it shows that the concrete has undergone carbonation. Phenolphthalein is a potent laxative, which The nonionized phenolphthalein molecule is colorless, the protonated phenolphthalein ion is an orange, and the deprotonated phenolphthalein ion is fuschia. Whether the cement paste here is completely uncarbonated is unclear, despite the strong purple indicator color; a more complete assessment would require microscopic examination. reinforcement and with shrinkage. A strong, immediate, color change to purple suggests a pH that is rather higher, perhaps pH 9 or 10.Normal concrete pore solution is saturated with calcium hydroxide and also contains sodium and potassium hydroxide; the pH is typically 13-14. Phenolphthalein's pH sensitivity is exploited in other applications: concrete has naturally high pH due to the calcium hydroxide formed when Portland cement reacts with water. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. How do indicators not affect the pH?

[12] Phenolphthalein has been found to inhibit human cellular calcium influx via store-operated calcium entry (SOCE, see Calcium release activated channel § Structure).

Get the ebook FREE when you sign up to CEMBYTES, our Understanding Cement Newsletter - just click on the ebook image above. Other potential effects inflicted on exposure to phenolphthalein are eye irritation, skin irritation, fever from ingestion, increase in blood pressure and respiratory tract irritation. The doubly deprotonated (In2-) phenolate form (the anion form of phenol) gives the familiar pink color. [13], Phenolphthalein has been added to the European Chemicals Agency's candidate list for Substances of Very High Concern (SVHC).[14]. c) When adding acid to base the phenolphthalein indicator Remember Me Carbonation of concrete is associated with the corrosion of steel

It’s colorless.

Copyright Notice: material on this website is copyright © 2005-2020 by WHD Microanalysis Consultants Ltd. All rights reserved. After a year or so it may typically have reached a depth of perhaps 1 mm for dense concrete of low permeability made with a low water/cement ratio, or up to 5 mm or more for more porous and permeable concrete made using a high water/cement ratio. Phenolphthalein indicator solution applied to a fresh fracture surface through a concrete slab.

Since phenolphthalein is colourless in acid and intensely red in base, it is commonly used as a pH indicator in titrations and also as the active ingredient…, In general, organic compounds are substances that contain carbon (C), and carbon atoms provide the key structural framework that generates the vast diversity of organic compounds. …and phenol react to give phenolphthalein, which is similar in structure to fluorescein but lacks the oxygen linking two of the aryl rings. In a similar application, some spackling used to repair holes in drywall contains phenolphthalein. Aragonite may form in hot conditions.

When adding acid or base, the phenolphthalein changes color from colorless to pink at the end of the titration.

Phenolphthalein is here. [19], 3,3-Bis(4-hydroxyphenyl)-2-benzofuran-1(3, 3,3-Bis(4-hydroxyphenyl)isobenzofuran-1(3, InChI=1S/C20H14O4/c21-15-9-5-13(6-10-15)20(14-7-11-16(22)12-8-14)18-4-2-1-3-17(18)19(23)24-20/h1-12,21-22H, InChI=1/C20H14O4/c21-15-9-5-13(6-10-15)20(14-7-11-16(22)12-8-14)18-4-2-1-3-17(18)19(23)24-20/h1-12,21-22H, O=C1OC(c2ccccc12)(c3ccc(O)cc3)c4ccc(O)cc4, Except where otherwise noted, data are given for materials in their, Calcium release activated channel § Structure, "Phenolphthalein Exposure Causes Multiple Carcinogenic Effects in Experimental Model Systems", 10.1002/(SICI)1098-2280(1998)31:2<113::AID-EM3>3.0.CO;2-N, "3 Versions of Ex-Lax Are Recalled After F.D.A.

Where the solution remains colorless, the pH of the concrete is below 8.6, suggesting carbonation. Phenolphthalein's pH sensitivity is exploited in other applications: concrete has naturally high pH due to the calcium hydroxide formed when Portland cement reacts with water. Make your products visible globally with Elite Membership. The pH scale has a marking from 0 to 14 fro detecting acid and base. a) Phenolphthalein indicator is not affected by the pH of the solution. This is effected by its inhibiting thrombin and thapsigargin, two activators of SOCE that increase intracellular free calcium. Performance & security by Cloudflare, Please complete the security check to access. If the indicator turns purple, the pH is above 8.6. Phenolphthalein is used as a laxative to treat incomplete and infrequent bowel movement. When a base is added to a solution containing phenolphthalein, the equilibrium between the nonionized and the deprotonated states shifts in favor of the deprotonated state as H+ ions are removed from solution.

Completing the CAPTCHA proves you are a human and gives you temporary access to the web property. This is available from chemical suppliers. Phenolphthalein has been observed to cause cancers in animals, based on studies. If you are at an office or shared network, you can ask the network administrator to run a scan across the network looking for misconfigured or infected devices. As an indicator of a solution’s pH, phenolphthalein is colourless below pH 8.5 and attains a pink to deep red hue above pH 9.0.