litmus paper

1. Ammonia gas is colorless which can turn wet red litmus paper to blue.
   氨气是无色的，它可把湿的红色石蕊试纸变成蓝色。
2. Strong bases that turn litmus paper blue, they react with acids to yield salts, are caustic, and in concentrated form corrode tissues.
   它们与酸作用成为中性盐；它们是苛性的，其浓缩物可腐蚀有机组织。
3. Test: turns blue litmus paper red.
   做个试验吧，能把蓝色的石蕊试纸变成红色。
4. Litmus paper can be used as an indicator of the presence of acid in a solution. We test the liquid for acidity with a strip of litmus paper.
   我们用一条石蕊试纸来试验这液体是不是酸性的。
5. Neutral reaction by litmus indicating paper.
   石蕊试纸呈中性反应。

noun

1. unsized paper treated with litmus for use as an acid-base indicator