Ionization Energies Lecture Demonstrations
Alkali Metals and Water
Show the reaction of small pieces of Li, K, and Na with water (universal indicater may be added to demostrate formation of a basic solution). A layer of paint thinner on the water can prevent hydrogen explosions, while making its formation visible .
The reactivity of the alkali metals with water depends strongly on the hydration energy of the ions as well as the ionization potential.
1. The reactions may be unpredictable, due to the formation and explosion of hydrogen. It's safer to contain the water in a petri dish rather than a beaker.
2. during long storage, potassium may form peroxide coatings that are explosive when cut with a spatula.