What is paper indicator?

Answer 1

paper thet measures pH is the measure of the acidity or alkalinity of a solution. It is formally a measure of the activity of dissolved hydrogen ions (H+), but for very dilute solutions, the molarity (molar concentration) of H+ may be used as a substitute with little loss of accuracy.[1] In solution, hydrogen ions occur as a number of cations including hydronium ions (H3O+).[ Hydrion is a trademarked name for a popular line of compound pH indicators, marketed by Micro Essential Laboratory, Inc. exhibiting a series of color changes (typically producing a recognizably different color for each pH unit) over a range of pH values. Although solutions are available, the most common forms of Hydrion are a series of papers impregnated with various mixtures of indicator dyes. It is considered a "universal indicator".

Answer 2

A paper indicator is a security feature often found in documents or certificates that helps to prove their authenticity. It can include watermarks, security threads, or other embedded features that are difficult to replicate, making it harder to forge or counterfeit the document.