石蕊
4.absorbent paper full of litmus; it is turned red by acids and blue by alkalis.
5.any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water.
6.any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt.
7.Connect 2 oxidation sulfur Shi Rui to try juice, if do not heat, after is litmus erubescent whether change by oneself a primary colors?
8.A water-soluble blue powder derived from certain lichens that changes to red with increasing acidity and to blue with increasing basicity.
9.Any of various substances, such as litmus or phenolphthalein, that indicate the presence, absence, or concentration of another substance or the degree of reaction between two or more substances by means of a characteristic change, especially in color.
