A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several commercially available universal pH indicators, most are a variation of a formula patented by Yamada in 1933. Details of this patent can be found in Chemical Abstracts. Experiments with Yamada's universal indicator are also described in the Journal of Chemical Education.
A universal indicator is usually composed of water, 1-Propanol, phenolphthalein, sodium hydroxide, methyl red, bromothymol blue, Sodium bisulfite, and thymol blue . The colours that indicate the pH of a solution, after adding a universal indicator, are
The colours from yellow to red indicate an acidic solution, colours blue to violet indicate alkali and green colour indicates that a solution is neutral.
Wide-range pH test papers with distinct colours for each pH from 1 to 14 are also available. Colour matching charts are supplied with the specific test strips purchased.
referenceEver curious about what that abbreviation stands for? fullforms has got them all listed out for you to explore. Simply,Choose a subject/topic and get started on a self-paced learning journey in a world of fullforms.
Allow To Receive Free Coins Credit 🪙