Several alkali metals and alkaline earth metals when dissolved in `NH_3` produce a bright blue solution.
This bright blue solution is due to

Options

A. solvated metal ion.
B. solvated electron.
C. high extent of hydration.
D. All of these.

Answer

To solve the question regarding the bright blue solution produced when several alkali metals and alkaline earth metals are dissolved in ammonia, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Context**:
- When alkali metals (like sodium, potassium) and alkaline earth metals (like calcium, magnesium) are dissolved in liquid ammonia, they form a solution that exhibits a bright blue color.

2. **Identifying the Cause of the Blue Color**:
- The blue color of the solution is primarily due to the presence of solvated electrons. When metals dissolve in ammonia, they release electrons which become solvated (surrounded by ammonia molecules).

3. **Absorption of Light**:
- These solvated electrons can absorb energy from light. Specifically, they absorb energy corresponding to the red region of the visible spectrum.

4. **Transmitted Light**:
- When the solvated electrons absorb red light, they become excited and then re-emit light. The light that is transmitted through the solution is not red, but rather blue, because the red light has been absorbed.

5. **Conclusion**:
- Therefore, the bright blue color of the solution is due to the presence of solvated electrons (ammoniated electrons) that absorb red light and transmit blue light.

### Final Answer:
The bright blue solution is due to the presence of solvated electrons (ammoniated electrons).

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