Write colours and magnetic behaviour of liquid NH3 solution in cold and hot conditionl

Dear student 

The redox chemistry of sodium in liquid ammonia is fairly complex. Solvated electrons form (to give the blue colour). As more metal is added the electrons COUPLE to form bronzes, reducing conductivity.

Ammonia is a water like solvent, that allows much more basic chemistry. When sodium is added to liquid ammonia, a beautiful blue colour forms, which is attributed to a solvated electron, which has a fairly long lifetime. On further reduction (i.e. addition of further sodium), the electrons are conceived to couple (i.e. 2 electrons are solvated by a cluster of ammonia molecules) to give the so called sodium bronze (and a reduction in electrical conductivity). These are very beautiful reactions to do, though admittedly smelly and time consuming.

The acid base chemistry of any solvent is limited to the properties of the solvent. Liquid ammonia solvents allow much more basic chemistry than is possible in water. The blue colour is the solvated electron, an electron that is stabilized by several ammonia molecules. Solvated electrons are also possible in water, but in this solvent the electrons have a vanishingly short lifetime. Note that this reaction should be demonstrated in 2nd year inorganic chemistry: you need a cylinder of ammonia gas, and a condenser cooled by dry ice and acetone to comdemse the ammonia.