What Color Does pH Paper Turn With Bleach?

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Litmus paper is red, litmus paper is blue, put these papers in a liquid or a gas and its hydrogen ion concentration will shine true. Litmus paper, or pH paper, is a tool that scientists use to discover whether a liquid or gas is an acid or a base. You can use litmus paper to see whether bleach is an acid or a base by examining what color the paper turns.

pH Scale

The pH scale is a test of the hydrogen ion concentration of a liquid or a gas. A neutral solution sits around a 7 on the pH scale. Anything between 0 and 7 is considered an acid and anything between 7 and 14 is considered a base.

The Litmus Test

The small, rectangular, red or blue paper strips of litmus paper are chemically treated so that they change color under certain conditions. For example, if a red piece of litmus paper is put in a base, it will turn blue. On the other hand, a blue piece of litmus paper put in an acid will turn red. If you have a gas or a liquid with a neutral pH level, neither the red nor blue litmus paper will change color when introduced to the substance in question. You should always test a substance with both the red and blue litmus papers to make sure the substance isn't neutral.


Liquid bleach, such as that found in laundry and household cleaners, has a pH level of approximately 11, according to Oregon State University's Environmental Health & Safety Office. This means that bleach is a base. Since it is a base, red litmus paper will turn blue when introduced to liquid bleach, and blue litmus paper won't change color.


About the Author

Rosemary Peters holds a Bachelor of Science in electrical engineering and a Master of Science in science communication. She has worked on editorial and design content across several publications, including "The Beacon" and "International Innovation." She has also spent time working in the Science radio unit at the BBC.

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  • George Doyle/Stockbyte/Getty Images

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