Phenolphthalein is a weak, colorless acid that changes color when it touches acidic (turns orange) or basic (turns pink/fuchsia) substances. People used to take it as a laxative (not recommended today, as ingesting high amounts may cause cancer). Use gloves when handling this chemical, as your skin can absorb it on contact. I’ll show you how:
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Materials:
- 2 test tubes
- sodium carbonate (washing soda)
- phenolphthalien (liquid)
- medicine dropper
- water
- test tube stoppers
- gloves and goggles
Download Student Worksheet & Exercises
Sprinkle a tiny amount of sodium carbonate into the bottom of your test tube. Fill your test tube partway with water (the solution should still be clear). Add a few drops of phenolphthalein (which is clear inside the dropper), cap, and shake.
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