FTP, name this mixture that, when absorbed onto filter paper, will turn the paper from purple to blue or red in the presence of a base or acid, respectively.
Archil is a similar substance to this that is derived from the same lichens like The Netherlands fungus Lecanora tartarea but by a different process. It is water-soluble, and chlorine gas has the ability to change its (*) color from blue to white. Because it can not detect specific values of the quantity it measures, devices like universal indicators are often used instead. FTP, name this mixture that, when absorbed onto filter paper, will turn the paper from purple to blue or red in the presence of a base or acid, respectively.
Archil is a similar substance to this that is derived from the same lichens like The Netherlands fungus Lecanora tartarea but by a different process.
{Litmus} (accept things like “Litmus Test” and “Litmus Paper”; prompt on “pH Paper” or “pH Test”)