Question

Alkali metals dissolve in ammonia to give a blue solution which is conducting in nature due to:

• A. ammoniated electrons
• B. loss of electrons
• C. ammoniated cations
• D. both $A$ and $C$

Answer 1

The correct option is D both $A$ and $C$

All alkali metals dissolve in liquid ammonia giving deep blue solutions which are conducting in nature. These solutions contain ammoniated cations and ammoniated electrons as shown: $M+(x+y)N{H}_3\to M^{+}(N{H}_3{)}_x+e^{-}(N{H}_3{)}_y$
The blue colour of the solution is considered to be due to ammoniated electrons which absorb energy corresponding to red region of the visible light for their excitation to higher energy levels. The transmitted light is blue which imparts blue colour to the solutions. The electrical conductivity of the solution is due to both ammoniated cations and ammoniated electrons. Both cation and electron are solvated (ammoniated). They conduct electricity as they are charged particles and can freely move in the solution.