Question

When alkali metal are dissolved in liquid ammonia the blue colour of solution is due to

• A. Ammoniated electron
• B. Ammoniated cation
• C. Both
• D. Alkali metal only

Hint:

Blue colour in liquid ammonia solution is due to solvated electrons.

Answer 1

The Correct Option is A

Concept:
Alkali metals dissolve in liquid ammonia producing solvated electrons.
Step 1:
When alkali metal dissolves: \[ M \rightarrow M^{+}+e^{-} \]
Step 2:
The released electron becomes surrounded by ammonia molecules. \[ e^{-}(NH_{3}) \] This is called ammoniated electron.
Step 3:
These ammoniated electrons absorb visible light and impart blue colour.
Step 4:
Hence blue colour is due to: \[ \boxed{\text{Ammoniated electron}} \] \[ \boxed{\text{Correct Option = (1)}} \]