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Phenolphthalein is slightly soluble in water and usually is dissolved in alcohols in experiments. It is a weak acid, which can lose H + ions in solution. The nonionized phenolphthalein molecule is colorless and the double deprotonated phenolphthalein ion is fuchsia. Further proton loss in higher pH occurs slowly and leads to a colorless form.
phenolphthalein (CAS number 77-09-8) resorcinol dibenzoate (CAS number 94-01-9) xestoquinone This page was last edited on 21 August 2019, at 06:58 ...
Chemical structure of phenolphthalein, a common phthalein dye. Phthalein dyes are a class of dyes mainly used as pH indicators, due to their ability to change colors depending on pH. [1] They are formed by the reaction of phthalic anhydride with various phenols. They are a subclass of triarylmethane dyes. Common phthalein dyes include ...
Solution: The main components of a universal indicator, in the form of a solution, are thymol blue, methyl red, bromothymol blue, and phenolphthalein. This mixture is important because each component loses or gains protons depending upon the acidity or alkalinity of the solution being tested. It is beneficial to use this type of universal ...
For example, hydrochloric acid, HCl, is a strong acid. HCl(aq) → H + (aq) + Cl − (aq) A strong base is one that is fully dissociated in aqueous solution. For example, sodium hydroxide, NaOH, is a strong base. NaOH(aq) → Na + (aq) + OH − (aq) Therefore, when a strong acid reacts with a strong base the neutralization reaction can be ...
For optimal accuracy, the color difference between the two species should be as clear as possible, and the narrower the pH range of the color change the better. In some indicators, such as phenolphthalein, one of the species is colorless, whereas in other indicators, such as methyl red, both species confer a color. While pH indicators work ...
Phenols are more acidic than typical alcohols. The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pK a is usually between 10 and 12).
In another comparison of Lewis and Brønsted–Lowry acidity by Brown and Kanner, [19] 2,6-di-t-butylpyridine reacts to form the hydrochloride salt with HCl but does not react with BF 3. This example demonstrates that steric factors, in addition to electron configuration factors, play a role in determining the strength of the interaction ...