It USES distilled water and alcohol to refine water soluble acid and alkali of sample and then test the extractive with PH indicator.

In the form of a water solution or as litmus paper, it is the oldest and most-used indicator of whether a substance is an acid or a Base.

A white or pale yellow crystalline powder, C20H 14o 4, used as an acid-base indicator, in making dyes, and in medicine as a laxative.