MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
Litmus test for amine solution. This piece of litmus paper has been turned blue by being dipped in a solution of an amine, indicating that the solution is alkaline. An amine is an organic nitrogen-containing chemical. Amines form alkaline solutions in water. Litmus paper, which uses a plant-based dye, is an acid-base indicator. It turns blue in alkaline solutions, and red in acidic solutions.
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