A solution of sodium in liquid ammonia is blue in colour due to : — s Block Elements Chemistry Question

💡 Solution & Explanation

Step 1: When sodium dissolves in liquid ammonia, it ionizes to form sodium cations and free electrons, both of which are solvated by ammonia molecules. Step 2: The equation is Na + (x+y)NH3 -> [Na(NH3)x]+ + [e(NH3)y]-. These solvated (ammoniated) electrons absorb energy in the red region of the visible light spectrum. Step 3: The absorbed light promotes the electrons to an excited state, and the complementary blue light is reflected/transmitted, resulting in a blue solution. Therefore, option (b) is the correct choice.