the concentrated solution of alkali metals in liquid ammonia becomes blue due to

Options

A. Ammoniated electron
B. Ammoniated metal cations
C. Diamagetic nature of solution
D. Alkaline nature of metal

Answer

To solve the question regarding why the concentrated solution of alkali metals in liquid ammonia becomes blue, we can break it down step by step:

### Step 1: Understand the Components
- Alkali metals (Li, Na, K, Rb, Cs) are known for their alkaline nature.
- Liquid ammonia (NH3) is a solvent that can dissolve these metals.

**Hint:** Identify the characteristics of alkali metals and the properties of liquid ammonia.

### Step 2: Reaction of Alkali Metals with Liquid Ammonia
- When alkali metals dissolve in liquid ammonia, they react to form ammoniated metal ions and ammoniated electrons.
- The general reaction can be represented as:
\[ M + n NH_3 \rightarrow [M(NH_3)_n]^+ + e^- \]
where \( M \) is the alkali metal.

**Hint:** Focus on the products formed during the reaction of alkali metals with ammonia.

### Step 3: Formation of Ammoniated Electrons
- The ammoniated electrons are free electrons that are solvated by ammonia molecules.
- These electrons are responsible for the color change observed in the solution.

**Hint:** Consider how the presence of free electrons can affect the color of a solution.

### Step 4: Color of the Solution
- The blue color of the solution is attributed to the presence of these ammoniated electrons.
- The unpaired electrons absorb specific wavelengths of light, leading to the blue appearance.

**Hint:** Think about how electron transitions can lead to color changes in solutions.

### Step 5: Conclusion
- Therefore, the concentrated solution of alkali metals in liquid ammonia becomes blue due to the presence of ammoniated electrons.

**Final Answer:** The concentrated solution of alkali metals in liquid ammonia becomes blue due to ammoniated electrons.

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