rhizoverbBeta
DictionarylitmusRevealing test
noun

litmus

LIT-mus/ˈlɪtməs/

A dye whose color reveals acidity or alkalinity.

The litmus dye turns red in acid and blue in alkali.

A simple laboratory still life showing litmus dye as a purple liquid in a small open bottle, beside two clear test tubes in a minimal rack: one contains a red acidic test solution and the other a blue alkaline test solution.
Etymology
litmusMiddle Englishlichen dye

Middle English lit-mose named a dye obtained from lichens, probably with a name connecting dyeing and moss. Its blue color turns red in acid and returns to blue with alkalis, making it useful for chemical testing.

In context

Next Generation Science0:07
we will test the pH levels of four everyday substances using litmus paper litmus paper is a special type of paper that changes color when exposed to acidic or basic Solutions
Testing pH of Household Substances #ngscience

More examples

  • We dip litmus paper into vinegar to check its acidity.
  • A neutral solution leaves the litmus purple.
  • The students add a few drops of litmus to each sample.

Similar words

indicator
A broader term for substances that reveal particular chemical conditions.
dye
Names a coloring substance without implying an acid-base testing function.