PHENOLPHTHALEIN supplier Distributor Manufacturer in Kolkata West Bengal india

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 colourless in acidic solutions and magenta in basic solutions. It belongs to class of dyes known as phthalein dyes.

Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols for use in experiments. It is a weak acid, which can lose H+ ions in solution. The phenolphthalein molecule is colourless, and the phenolphthalein ion is pink.When a base is added to the phenolphthalein, the molecule ⇌ ions equilibrium shifts to the right, leading to more ionization as H+ ions are removed. This is predicted by Le Chatelier's principle.

Uses

pH indicator

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 (HIn+), providing an orange colouration. Between strongly acidic and slightly basic conditions, the lactone form (HIn) is colourless. The doubly deprotonated (In2-) phenolate form (the anion form of phenol) gives the familiar pink colour. In strongly basic solutions, phenolphthalein is converted to its In(OH)3− form, and its pink colour undergoes a rather slow fading reaction and becomes completely colourless above 13.0 pH.

Education

In a highly basic solution, phenolphthalein's slow change from pink to colourless as it is converted to its In(OH)3− form is used in chemistry classes for the study of reaction kinetics.

Entertainment

Phenolphthalein is used in toys, for example as a component of disappearing inks, or disappearing dye on the Hollywood Hair Barbie hair. 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 colour change threshold as hydrogen ions are released by the reaction:
To develop the hair and "magic" graphical patterns, the ink is sprayed with a solution of hydroxide, which leads to the appearance of the hidden graphics by the same mechanism described above for colour change in alkaline solution. The pattern will eventually disappear again because of the reaction with carbon dioxide. Thymolphthalein is used for the same purpose and in the same way, when a blue colour is desired.

Medical uses

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.

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.