When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.

When an alkali metal dissolves in liquid ammonia the solution can acqu

1.	When an alkali metal dissolves in liquid ammonia the solution can acquire different colours. Explain the reasons for this type of colour change.
Answer» Solution : SOLUTIONS in liquid ammonia : The alkali metals dissolve in liquid ammonia giving deep blue solutions which are conducting in nature. `M + (x + y) NH_(3) to [M(NH_(3))_(x)]^(+) + [e(NH_(3))_(y)]^(-)` The blue COLOUR of the solution is due to the ammoniated electron which absorbs energy in the visible region of light and thus imparts blue colour to the solution. The solutions are paramagnetic and on standingslowly liberate hydrogen resulting in the formation of amide. `M_((am))^(+)+e^(-)+NH_(3(l)) to MNH_(2(am))+(1)/(2)H_(2(g))` (where .am. DENOTES solution in ammonia.) In concentrated solution, the blue colour changes to BRONZE colour and becomes diamagnetic.