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Phenol red exists as a red crystal that is stable in air. Its solubility is 0.77 grams per liter (g/L) in water and 2.9 g/L in ethanol. [1] It is a weak acid with pK a = 8.00 at 20 °C (68 °F). A solution of phenol red is used as a pH indicator, often in cell culture.
Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 5.4 to 6.8. [2] The pH of a substance is determined by taking the negative logarithm of the Hydronium ion concentration and the indictor changes color due to the dissociation of H + ions. [3] The lambda max is at 572 nm. [4]
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.
o-Cresolphthalein is a phthalein dye used as a pH indicator in titrations. It is insoluble in water but soluble in ethanol . Its solution is colourless below pH 8.2, and purple above 9.8.
By reacting the bromopyrogallol red with niobium(V) in a tartrate medium at pH 6.0, an intense blue coloured 3:1 reagent was formed. The sensitivity and conditional selectivity of bromopyrogallol red was also studied and results show that trace amounts of silver can be detected from the formation of a ternary complex between 1,10-phenanthroline, bromopyrogallol red and silver ion.
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. [3] Phenolphthalein adopts different forms in aqueous solution depending on the pH of the solution.
Because ammonia is alkaline, the media contains phenol red, an indicator that changes from orange to pink when a pH increases above 8.1. When ammonia is increased to high enough concentrations, the media will change to a pink color, indicating the presence of urease production. [37]
A chlorophenol is any organochloride of phenol that contains one or more covalently bonded chlorine atoms. There are five basic types of chlorophenols (mono- to pentachlorophenol) and 19 different chlorophenols in total when positional isomerism is taken into account. Chlorophenols are produced by electrophilic halogenation of phenol with ...