Question

alkali metals dissolve in liquid ammonia to give deep blue solutions.give reason

Answer 1

All alkali metals Like Lithium, Sodium, potassium etc dissolves in liquid Ammonia to give deep blue coloured solution

Reason:

M + (x+y) NH3------------> M⁺(NH3)x                   +  e⁻ (NH3)y                                                                                  Ammoniated cation       Ammoniated Anion

When ordinary light falls on this solution then electrons absorb this energy and gets excited to higher levels corresponding to red region of visible light.As a result transmitted light is blue which imparts blue colour.

Answer 2

Ammoniated electrons absorb energy in the visible region of light so the solution is blue in colour.

Alkali metals namely Lithium, Sodium, Potassium, Rubidium, Cesium and Francium dissolve in liquid ammonia and give deep blue solutions. These solutions conduct electricity. They contain ammoniated cations and ammoniated electrons.

They are paramagnetic and liberate hydrogen if they are allowed to stand for some time. This leads to the formation of amides.

The colour of highly concentrated solutions changes from blue to bronze and they become diamagnetic.