Problem
Problem
All alkali metals dissolve in anhydrous liquid ammonia to give blue colour solution. It is the ammoniated electron which is responsible for the blue colour of the solution, and the electrical conductivity is due to the ammoniated cation, as well as the ammoniated electron, , values of and depend on the extent of solvation by . Dilute solutions are paramagnetic due to free ammoniated electrons. What happens if more alkali metals is allowed to react with concentrated liquid ammonia? a. Paramagnetic character of solvated electrons is retained b. Solvated electrons associate to form electron-pairs and paramagnetic character decreases c. Reducing character is increased d. Reducing character is not affectedIntuitive explanation
When you add excess alkali metal to concentrated ammonia, you're flooding the system with free electrons that can pair up with each other. The key insight is that electron pairing eliminates paramagnetism — paired electrons have opposite spins that cancel out, making the solution diamagnetic instead. Additionally, the solution transitions from blue (characteristic of isolated solvated electrons) to bronze or copper-colored, because paired electrons absorb light differently than unpaired ones. Think of it as a shift from a dilute "one electron per solvation cage" scenario to a concentrated regime where electrons find partners.
Intuitive explanation
When you add excess alkali metal to concentrated ammonia, you're flooding the system with free electrons that can pair up with each other. The key insight is that electron pairing eliminates paramagnetism — paired electrons have opposite spins that cancel out, making the solution diamagnetic instead. Additionally, the solution transitions from blue (characteristic of isolated solvated electrons) to bronze or copper-colored, because paired electrons absorb light differently than unpaired ones. Think of it as a shift from a dilute "one electron per solvation cage" scenario to a concentrated regime where electrons find partners.