Litmus test on an orange. A piece of blue litmus paper held against a freshly-cut face of an orange. The change of colour from blue to red means that

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Litmus test on an orange. A piece of blue litmus paper held against a freshly-cut face of an orange. The change of colour from blue to red means that the orange must be acidic. Oranges, like all citrus fruits, contain citric acid.

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Photo credit: © Science Photo Library / Alamy / Afripics
License: Licensed
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Keywords: acid, acidity, analysis, basic, blue, chemical, chemistry, citrus, confirmation, demonstration, experiment, food, foodstuff, fruit, laboratory, litmus, orange, paper, ph, red, school, science, simple, test