Question

All alkali and alkaline earth metals forms only blue colour solution in liquid ammonia

Answer 1

All alkali metal dissolve in liquid ammonia giving highly conducting deep blue solutions.These solutions contain ammoniated cations and ammoniated electrons as shown below:

M + ( x + y ) NH3   → M+  ( NH3 )x + e-(NH3)y

Dilute solutions of alkali metals in liquid ammonia are dark blue in colour but as the concentration increases above 3 M, the colour changes to copper-bronze and the solutions acquire metallic lustre due to formation of metal ion clusters.

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