# Transcript

NARRATOR

Liquid ammonia is a good polar solvent, rather like water. Using a mixture of dry ice and acetone, we can condense ammonia by cooling it below its boiling point of minus 33 degrees C. It was Sir Humphry Davy who, in 1807, first noticed that adding alkali metals, such as sodium, to liquid ammonia produces a blue solution. The colour comes from electrons released from the sodium atom which are solvated by ammonia molecules. As we increase the concentration of sodium, notice the formation of a bronze, highly conducting form of the sodium/liquid ammonia system.