Question

Read the following passage and answer the questions at the end of it.

Dilute solution of alkali metals in liquied$N{H}_3$ is blue. It is the ammoniated electron which is responsible for the blue color of the solution and the electrical conductivity is due to the ammoniated cation,

$\left[M\right(N{H}_3{)}_x{]}^{+}$ as well as the ammoniated electron, $\left[e\right(N{H}_3{)}_y{]}^{-}$, values of x and y depend on the extent of solvation $\left(byN{H}_3\right)$. Dilute solutions are paramagnetic due to free electrons.

What happens if alkali metal is allowed to react with concentrated ammonia solution?

• 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 affected

Answer 1

Answer: (B)

Solvated electrons associate to form electron-pairs and paramagnetic character decreases

If the concentration is increased then, above 3M solutions are copper-bronze colored and have a metallic luster.

This is because metal ion clusters are formed and this paramagnetic character decreases.