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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.
c 6 h 4 (ch 3) 2 + 7 + 1 / 2 o 2 → c 4 h 2 o 3 + 4 h 2 o + 4 co 2 Phthalic anhydride and maleic anhydride are recovered by distillation by a series of switch condensers . The naphthalene route (the Gibbs phthalic anhydride process or the Gibbs–Wohl naphthalene oxidation reaction) has declined relative to the o -xylene route.
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 ...
1,10-Phenanthroline (phen) is a heterocyclic organic compound. It is a white solid that is soluble in organic solvents. It is a white solid that is soluble in organic solvents. The 1,10 refer to the location of the nitrogen atoms that replace CH's in the hydrocarbon called phenanthrene .
Upon reduction, the very intense pink color of the cationic form of phenolphthalein fades to a faint yellow color. It is this form of phenolphthalein that is present in Kastle–Meyer test kits. In order to generate the intense pink color indicative of a positive test, the reduced phenolphthalein must be oxidized back to its normal, colored form.
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−O H) bonded directly to an aromatic hydrocarbon group. [1] The simplest is phenol, C 6 H 5 OH. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the ...
A Mass General Brigham emergency care doctor shares step-by-step guidance on how to administer the Heimlich maneuver to adults, children and yourself in a choking event.
Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38,000 M −1 cm −1 at 595 nm. [2]