Big Reaction: Cesium and water

Big Reaction: Cesium and water

Cesium and water
Cesium reacting with water.

I’m a sucker for beautiful color.

This reaction shows cesium dropping into water that contains phenolphthalein. The phenolphthalein (C20H14O4) acts as an indicator, turning pink when the solution turns basic. In this case, the base is CsOH, a product of 2H2O + Cs → 2CsOH + H2

The pulsed reaction is due to the phenomenon of cavitation. As the chemical reaction progresses, a bubble of heated water vapor forms, slowing the reaction. The cavity implodes as it cools, leading to another pulse of reaction and more cavitation.

Here’s the original video, from SciencePhotoLibrary:

More on why alkali metals explode. And more fun with Cesium.

Have a neat chemical or physical reaction you’d like to share? Tell us in the comments!

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