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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.
Three different points in an acid-base titration using phenolphthalein as the indicator. Phenolphthalein is widely recognized as one of the most commonly used acid-base indicators in chemistry. [12] Its popularity is because of its effectiveness in a broad pH range and its distinct colour transitions. [12]
A roll of universal indicator pape Colors of universal indicator. A universal indicator is a pH indicator made of a solution of several compounds that exhibit various smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. A universal indicator can be in paper form or present in a form of a solution ...
The Kastle–Meyer test is a presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used to detect the possible presence of hemoglobin. It relies on the peroxidase -like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into ...
Indicator: A substance that changes color in response to a chemical change. An acid–base indicator (e.g., phenolphthalein) changes color depending on the pH. Redox indicators are also used. A drop of indicator solution is added to the titration at the beginning; the endpoint has been reached when the color changes.
Some young Americans had a tough time finding a job last year. Companies were slow to hire in 2024 as workers quit their jobs less frequently, according to government data — a far cry from the ...
When you’re craving comfort, a warm, cozy bowl of soup may be just what the doctor ordered. And thanks to canned soups, you don’t have to spend hours in the kitchen to get your fix. But if you ...
Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O +) or hydrogen ions (H +) in the Arrhenius model. Normally, the indicator causes the color of the solution to change depending on the pH. Indicators can also show change in other physical properties; for example, olfactory indicators show change in their odor.