Search results
Results from the WOW.Com Content Network
In strongly basic solutions, phenolphthalein is converted to its In(OH) 3− form, and its pink color undergoes a rather slow fading reaction [6] and becomes completely colorless when pH is greater than 13. The pK a values of phenolphthalein were found to be 9.05, 9.50 and 12 while those of phenolsulfonphthalein are 1.2 and 7.70. [2]
It is advised to check the references for photos of reaction results. [1] Reagent testers might show the colour of the desired substance while not showing a different colour for a more dangerous additive. [2]
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 ...
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.
Aluminum pigments. Ultramarine (PB29): a synthetic or naturally occurring sulfur containing silicate mineral - Na 8–10 Al 6 Si 6 O 24 S 2–4 (generalized formula); Persian blue: made by grinding up the mineral Lapis lazuli.
Colorants (both dyes and pigments) are listed using a dual classification which use the Colour Index Generic Name (the prime identifier) and Colour Index Constitution Numbers. These numbers are prefixed with C.I. or CI, for example, C.I. Acid Orange 7 or C.I. 15510. (This abbreviation is sometimes mistakenly thought to be CL, due to the font ...
Paper form: It is a strip of coloured paper which changes colour to red if the solution is acidic and to blue, if the solution is basic. The strip can be placed directly onto a surface of a wet substance or a few drops of the solution can be dropped onto the universal indicator using dropping equipment.
This is an accepted version of this page This is the latest accepted revision, reviewed on 14 December 2024. For other color lists, see Lists of colors. This article relies largely or entirely on a single source. Relevant discussion may be found on the talk page. Please help improve this article by introducing citations to additional sources. Find sources: "List of colors" alphabetical ...