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 a concentrated solution of alkali metals in liquid ammonia becomes blue, we can break it down into the following steps:

### Step 1: Understanding Alkali Metals
Alkali metals are elements found in Group 1 of the periodic table, which include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). These metals are known for their high reactivity and tendency to lose one electron to form cations.

**Hint:** Remember that alkali metals are highly reactive and form cations by losing one electron.

### Step 2: Reaction with Liquid Ammonia
When alkali metals are dissolved in liquid ammonia, they react to form ammoniated metal ions and free electrons. The general reaction can be represented as:
\[ M + n \text{NH}_3 \rightarrow \text{[M(NH}_3\text{)}_n]^+ + e^- \]
Here, \( M \) is the alkali metal, and \( e^- \) represents the free electron.

**Hint:** Focus on the products formed when alkali metals react with ammonia.

### Step 3: Formation of Ammoniated Electrons
The free electrons that are produced in the solution become solvated or "ammoniated" by the ammonia molecules. This results in the formation of what is known as "ammoniated electrons," which are responsible for the blue color observed in the solution.

**Hint:** Recall that the term "ammoniated electrons" refers to electrons that are surrounded by ammonia molecules.

### Step 4: Color of the Solution
The blue color of the concentrated solution of alkali metals in liquid ammonia is primarily due to the presence of these ammoniated electrons. The absorption of light by these electrons leads to the characteristic blue color.

**Hint:** The color change is linked to the presence of ammoniated electrons in the solution.

### Step 5: Conclusion
Based on the understanding of the reactions and the formation of ammoniated electrons, we can conclude that the correct answer to the question is that the blue color in the concentrated solution of alkali metals in liquid ammonia is 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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