The simplest method to develop the pH of a substance – to figure out whether it is acidic or alkaline – is to use red and also blue litmus papers. Red litmus paper reacts to alkaline building material by transforming blue, while blue litmus paper reacts to acidic building material by transforming red.

You are watching: If blue litmus paper turns red


TL;DR (Too Long; Didn"t Read)

When red litmus document comes into call with any type of alkaline substance, it turns blue. Some instances of alkaline substances space ammonia gas, milk the magnesia, baking soda and also limewater.


Litmus paper is make from hardwood cellulose the is infused with an aqueous equipment consisting mostly of lichens. Throughout the manufacturing of red litmus paper, the lichens space left to ferment in potassium carbonate, ammonia, and a tiny amount of sulfuric or hydrochloric acid. The massive is then blended with chalk. The is this equipment that makes the document pH active. White record is impregnated with the solution and left to dry in open air. The process for blue litmus file is similar, yet no sulfuric or hydrochloric acid is added to the solution.


The pH scale varieties from zero to 14, with a pH of 7 gift neutral, a pH much less than 7 gift acidic, and a pH better than 7 gift alkaline. Ammonia gas transforms red litmus record blue since it has actually a pH of 11.6. Milk that magnesia is slightly much less alkaline, v a pH level of roughly 10.5. Sodium bicarbonate, otherwise well-known as baking soda, has actually a lower pH level still, at around 8.4, however it is quiet alkaline since it is over the neutral pH value of 7. Other examples of building materials that revolve red litmus document blue incorporate sodium hydroxide (caustic soda), calcium hydroxide (limewater) and also alkaline soils.


Red litmus paper is dipped right into a systems to create whether a problem is acidic or alkaline. In one acidic or neutral solution, red litmus record remains red. In an alkaline solution, red litmus document turns blue. Once an alkaline link dissolves in water, it produces hydroxide ions, which reason the equipment to come to be alkaline. Red litmus paper can also be used to test the pH of a water-soluble gas by dampening the paper and exposing it come the gas.


While red and blue litmus papers can expose whether a substance is acidic or alkaline, they can not tell friend the specific pH value of that substance. However, litmus records are simple to handle and also use. They provide instantaneous readings and provide accurate results many of the time.

See more: Solved: 6 Is 25 Percent Of What Number = 24, 6 Is 25 Percent Of What Number


Claire is a writer and also editor with 18 years' experience. She writes around science and also health because that a variety of digital publications, including Reader's Digest, HealthCentral, Vice and also Zocdoc.