Question

The metal which dissolves in liquid ammonia to give a blue-black solution due to formation of solvated electron is

• A. aluminum
• B. gallium
• C. calcium
• D. silicon
• E. garmanium

Answer 1

The Correct Option is C

When metals dissolve in liquid ammonia, they form solvated electrons. These solvated electrons are responsible for the characteristic blue-black color of the solution. Among the given options, calcium is the metal that forms solvated electrons in liquid ammonia, resulting in a blue-black solution. Other metals like aluminum, gallium, silicon, and germanium do not form such a solution in liquid ammonia.

The correct option is (C) : Calcium

Answer 2

The metal that dissolves in liquid ammonia to give a blue-black solution due to the formation of solvated electrons is calcium.

Explanation:

Alkali metals (like sodium, potassium, etc.) and alkaline earth metals (like calcium, strontium, barium) can dissolve in liquid ammonia. The dissolved metal atoms lose their valence electrons, which become solvated by ammonia molecules. These solvated electrons are responsible for the characteristic blue color of the solution. At higher concentrations, the solution becomes bronze-colored.

The general reaction can be represented as:

\(M \rightarrow M^+ + e^-\)

\(e^- + xNH_3 \rightarrow [e(NH_3)_x]^-\) (solvated electron)

The solvated electrons absorb light in the visible region, giving the solution its blue color. At higher concentrations, metal ions and solvated electrons associate to form metal clusters, leading to a bronze color.

Of the given options, calcium is the only alkaline earth metal, so it is the correct answer.

Therefore, the answer is calcium.