Universal indicator

Universal indicator is a pH indicator that transitions through numbers 3-12 (on the pH chart) to indicate the acidity or alkalinity of solutions. Although there are a number of commercially available universal pH indicators, most are a variation of a formula patented by Yamada in 1923. 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 typically composed of water, methanol, propan-1-ol, phenolphthalein sodium salt, methyl red sodium salt, bromothymol blue monosodium salt, and thymol blue monosodium salt

Here are the colours that indicate the acidity of a solution, after adding UI:

1. Very acidic - Red

2. Acidic - Orange/Yellow

3. Neutral - Green

4. Basic/base/alkali - Blue

5. Very basic/base/alkali - Purple

See also


Search another word or see alkali-blueon Dictionary | Thesaurus |Spanish
Copyright © 2015, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature