Alkali metals dissolve in liquid ammonia to give a blue coloured solution. Why does the solution turn bronze when the concentration is increased? 

Asked by jazcel | 9th Jan, 2016, 05:08: PM

Expert Answer:

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 )+ 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.

Answered by Prachi Sawant | 10th Jan, 2016, 03:43: PM