Question

The alkali metals dissolve in liquid ammonia, it is found that

• A. The blue colour changes to bronze with increasing concentration
• B. Blue solutions are paramagnetic but bronze coloured solutions are diamagnetic
• C. Blue colour is due to the presence of solvated electrons
• D. All the facts given above are correct

Hint:

In liquid ammonia, alkali metals form solvated electrons, which lead to the characteristic blue colour, and this colour changes with concentration.

Answer 1

The Correct Option is D

Step 1: Alkali metals in liquid ammonia.
When alkali metals dissolve in liquid ammonia, they form blue solutions due to the presence of solvated electrons. The blue colour is a result of these solvated electrons being in an excited state. As the concentration of the alkali metal increases, the solution turns bronze due to the aggregation of solvated electrons.
Step 2: Paramagnetism and diamagnetism.
The blue solution is paramagnetic because of the unpaired solvated electrons, whereas the bronze solution becomes diamagnetic as the electrons pair up.
Step 3: Conclusion.
Therefore, all the facts given above are correct. The correct answer is (4) All the facts given above are correct.