All alkali metals dissolve in anhydrous liquid ammonia to give a blue-coloured solution
CHEMISTRY · Single correct · A Level · Chemistry · Group 2 elements (alkaline earth metals) · Group 2 elements (alkaline earth metals)
Problem
All alkali metals dissolve in anhydrous liquid ammonia to give a blue-coloured solution. Ammoniated electrons cause the blue colour, and electrical conductivity is due to both the ammoniated cation, [M(NH3)x]+, and the ammoniated electron, [e(NH3)y]−; x and y depend on the extent of solvation by NH3. Dilute solutions are paramagnetic due to free ammoniated electrons. What happens if more alkali metal is allowed to react with concentrated liquid ammonia?
(1) Paramagnetic character of solvated electrons is retained.
(2) Solvated electrons associate to form electron pairs and paramagnetic character decreases.
(3) Reducing character is increased.
(4) Reducing character is not affected.