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Phenolphthalein (/ fɛˈnɒl (f) θəliːn / [citation needed]feh-NOL (F)-thə-leen) is a chemical compound with the formula C 20 H 14 O 4 and is often written as " HIn ", " HPh ", " phph " or simply " Ph " in shorthand notation. Phenolphthalein is often used as an indicator in acid–base titrations. For this application, it turns colorless in ...
Reactions with indicators: bases turn red litmus paper blue, phenolphthalein pink, keep bromothymol blue in its natural colour of blue, and turn methyl orange-yellow. The pH of a basic solution at standard conditions is greater than seven. Bases are bitter. [5]
Acids and bases. A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. [1] Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O +) or hydrogen ...
Food pyramid (nutrition) Appearance. The USDA 's original food pyramid, from 1992 to 2005 [ 1 ] A food pyramid is a representation of the optimal number of servings to be eaten each day from each of the basic food groups. [ 2 ] The first pyramid was published in Sweden in 1974. [ 3 ][ 4 ][ 5 ] The 1992 pyramid introduced by the United States ...
Bromothymol blue (also known as bromothymol sulfone phthalein and BTB) is a pH indicator. It is mostly used in applications that require measuring substances that would have a relatively neutral pH (near 7). A common use is for measuring the presence of carbonic acid in a liquid. It is typically sold in solid form as the sodium salt of the acid ...
Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue.
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.
New research suggests a compound found in a wide variety of products — from cosmetics to air fresheners to detergents and soaps — may send a signal to an area of the brain that triggers the ...