Phenolphthalein
Phenolphthalein is a chemical compound with the formula C20H14O4 and is often written as "HIn" or "phph" in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.
Phenolphthalein's common use is as an indicator in acid-base titrations. It also serves as a component of universal indicator, together with methyl red, bromothymol blue, and thymol blue.
Phenolphthalein adopts four different states in aqueous solution: Under very strongly acidic conditions, it exists in protonated form, providing an orange coloration. Between strongly acidic and slightly basic conditions, the lactone form is colorless. The singly deprotonated phenolate form (the anion form of phenol) gives the familiar pink color. In strongly basic solutions, phenolphthalein's pink color undergoes a rather slow fading reaction and becomes completely colorless above 13.0 pH.
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. As the concrete reacts with carbon dioxide in the atmosphere, pH decreases to 8.5-9. When a 1% phenolphthalein solution is applied to normal concrete, it turns bright pink. However, if it remains colorless, it shows that the concrete has undergone carbonation. In a similar application, spackling used to repair holes in drywall contains phenolphthalein. When applied, the basic spackling material retains a pink coloration; when the spackling has cured by reaction with atmospheric carbon dioxide, the pink color fades.
Phenolphthalein is used in toys, for example as a component of disappearing inks, or disappearing dye on the Hollywood Hair Barbiehair. In the ink, it is mixed with sodium hydroxide, which reacts with carbon dioxide in the air. This reaction leads to the pH falling below the color change threshold as hydrogen ions are released by the reaction:
Phenolphthalein has been used for over a century as a laxative, but is now being removed from over-the-counter laxatives because of concerns over carcinogenicity.Thymolphthalein is a related laxative made from thymol. See Phenolsulfonphthalein also.
Despite concerns regarding its carcinogenicity, the use of phenolphthalein as a laxative is unlikely to cause ovarian cancer. Phenolphthalein has been found to inhibit human cellular calcium influx via store-operated calcium entry (SOCE, see Calcium release activated channel § Structure). This is effected by its inhibiting thrombin and thapsigargin, two activators of SOCE that increase intracellular free calcium.
Phenolphthalein has been added to the European Chemicals Agency's candidate list for Substances of Very High Concern (SVHC)
A reduced form of phenolphthalein, phenolphthalin, which is colorless, is used in a test to identify substances thought to contain blood, commonly known as the Kastle-Meyer test. A dry sample is collected with a swab or filter paper. A few drops of alcohol, then a few drops of phenolphthalin, and finally a few drops of hydrogen peroxide are dripped onto the sample. If the sample contains hemoglobin, it will turn pink immediately upon addition of the peroxide, because of the generation of phenolphthalein. A positive test indicates the sample contains hemoglobin and, therefore, is likely blood. A false positive can result from the presence of substances with catalytic activity similar to heme. This test is not destructive to the sample; it can be kept and used in further tests. This test has the same reaction with blood from any animal, so further testing would be required to determine whether it originates from a human.
Dubichem chemicals international is a leading supplier, manufacturer and exporter of Phenolphthalein in Dubai, Ajman, Abu- Dhabi, Sharjah, Fujairah, Turkey, Saudi Arabia, Qatar, Kuwait, United Arab Emirates, Oman, Singapore, Malaysia, Indonesia, Lebanon, Greece, India, Sudan, Ghana, Madagascar, Kenya, Nigeria, Zimbabwe, Uganda, Ethiopia, Namibia, Mauritius, South Africa ,Europe & Globally for any queries mail us at Dubichem@gmail.com and for more related products visit www.dubichem.com
Phenolphthalein Supplier, Exporter in Fujairah, Dubai, UAE, Middle East, Gulf, Asia
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