A School Experiment

By Lidia Minza
"Vasile Alecsandri" High School, Galacti, Romania

Sodium will react with water to make sodium hydroxide base and hydrogen gas:

The reaction is exothermic enough to cause the flammable hydrogen gas to ignite explosively with oxygen in the atmosphere to make new water molecules:

For these reasons, sodium is usually kept under mineral oil to keep it from reacting with these common substances.

The indicator (phenolphthalein) shows that sodium hydroxide is produced: the solution changes to deep red.

All the alkali metals react with water to produce elementary hydrogen and the corresponding alkali hydroxides. The reactivity increases with increasing periodic number. The metals rubidium and cesium explode when brought into contact with oxygen.

This experiment was performed with XI B class from “Vasile Alecsandri” High School, Galati, Romania.