litmus paper

noun

1. a strip of paper impregnated with litmus, used as a chemical indicator.

Word History and Origins

Origin of litmus paper¹

First recorded in 1795–1805

Example Sentences

A blue litmus paper turns red in acids while a red litmus paper turns blue in basic solutions.

From Science News For Students

So they are a litmus paper for wider fertility—not a significant driver of Israeli birthrates.

From The Daily Beast

The solution of lead must contain acid; and if by keeping it does not change litmus-paper, acid must be added till it does.

From Project Gutenberg

The blue litmus paper became red showing the presence of an acid.

From Project Gutenberg

It turns litmus paper red; sometimes very slightly, and occasionally even not at all.

From Project Gutenberg

Litmus-paper, indigo blue or other vegetable colours are at once bleached.

From Project Gutenberg

Then add enough of the bicarbonate of soda solution till it turns the litmus paper back to blue.

From Project Gutenberg