English Dictionary

litmus paper

noun

(chemistry) paper containing a water-soluble pH indicator composed of a mixture of different dyes extracted from certain lichens. The resulting piece of paper is used to test materials for acidity, turning red when acidic and blue when alkaline.

I used litmus paper to test the acidity of the solution.

意味（1）

(chemistry) paper containing a water-soluble pH indicator composed of a mixture of different dyes extracted from certain lichens. The resulting piece of paper is used to test materials for acidity, turning red when acidic and blue when alkaline.