A universal indicator is a mixture of indicators that measures the acidity of a solution with relative accuracy. It changes colors in a wide variety of media, turning red in a highly acidic medium, yellow-green in a neutral medium, and purple in an extremely basic medium. It consists of five indicators: thymol blue, methyl orange, methyl red, bromothymol blue, and phenolphthalein. To increase its versatility in use, this mixture is applied to paper and dried.
This reagent is considered nonhazardous according to GHS classifications. Treat all reagents with caution.
Dozens of experiments you can do at home
One of the most exciting and ambitious home-chemistry educational projects