What is Litmus paper?
[[File:Litmus paper.JPG|thumb|Litmus paper being used]] '''Litmus''' is a [[mixture]] which is made from different [[dye]]s which can be taken from [[lichen]]s. It is [[aqueous solution|water-soluble]]. It is used to tell whether a solution is an [[acid]] or an [[alkali]]. Litmus is put onto [[filter paper]]. This paper is then called 'litmus paper'. The paper can then be used to give a rough indication of the [[pH]] value of a solution. Blue litmus paper will turn red, when [[acid]] is present; red litmus paper will turn blue when [[alkaline]]s are present. At room temperature, this usually happens for pH values between 4.5 and 8.3. Alternatively, a solution can be prepared which works the same way, but does not need the paper. Although litmus and litmus paper can determine if any substance is acidic or alkaline, it cannot determine its pH.<ref>{{Cite web|title=litmus paper|url=https://www.owp.csus.edu/glossary/litmus-paper.php#:~:text=The%20use%20of%20litmus%20paper,chart%20to%20indicate%20pH%20level.|access-date=2025-03-06|website=www.owp.csus.edu}}</ref> [[Universal indicator]] can be used to determine its exact pH.<ref>{{Cite web|last=Karmakar|first=Swarna|date=2022-01-10|title=What is Universal Indicator? - A Complete Guide|url=https://www.labkafe.com/blog/universal-indicator-what-is-it-why-do-we-need-it-and-how-to-use-labkafe/|access-date=2025-03-06|website=Labkafe Blog|language=en-US}}</ref> == Related pages == *[[pH#Indicators]] {{-}} {{chem-stub}} [[Category:Chemical compounds]] [[Category:Analytical chemistry]] [[Category:Physical chemistry]]