The alkali metals dissolve in liquid `NH_(3)`, it is found that:

Options

A. The dilute solution are blue but the colour changes to bronze with increasing concentration
B. The blue colour is due to presence of solvated electrons
C. The blue solutions are paramagnetic but the bronze coloured solutions are diamagnectic
D. All the facts given above are found

Answer

To solve the question regarding the behavior of alkali metals when dissolved in liquid ammonia (NH3), we can break down the information into clear steps:

### Step-by-Step Solution

1. **Dissolution of Alkali Metals in Liquid NH3**:
- When alkali metals (M) dissolve in liquid ammonia, they dissociate to form M⁺ ions and release electrons. The reaction can be represented as:
\[ M \rightarrow M^+ + e^- \]

**Hint**: Remember that alkali metals have a tendency to lose one electron to achieve a stable electronic configuration.

2. **Formation of Solvated Ions**:
- The M⁺ ions are surrounded by NH3 molecules, forming a solvated ion. This is due to coordinate bonding where NH3 acts as a Lewis base donating a lone pair to the metal ion.
- The structure can be visualized as:
\[ [M^+(NH_3)_n] \]
where n indicates the number of NH3 molecules coordinated to the M⁺ ion.

**Hint**: Visualize the coordination sphere around the metal ion to understand how solvated ions are formed.

3. **Formation of Solvated Electrons**:
- The released electrons (e⁻) also become solvated by NH3 molecules, forming solvated electrons. This can be represented as:
\[ [e^-(NH_3)_m] \]
where m indicates the number of NH3 molecules surrounding the electron.

**Hint**: Consider how the electron is stabilized in the solution by surrounding it with NH3 molecules.

4. **Color of the Solution**:
- Dilute solutions of alkali metals in liquid NH3 appear blue due to the presence of solvated electrons. The blue color is a result of electronic transitions of these solvated electrons.
- As the concentration of the solution increases (greater than 3M), the color changes to bronze due to the formation of clusters of metal ions, which gives the solution a metallic luster.

**Hint**: Recall that color changes in solutions can indicate different electronic environments or species present.

5. **Magnetic Properties**:
- In dilute solutions, the solvated electrons are unpaired, making the solution paramagnetic (attracts a magnetic field).
- In concentrated solutions, the electrons become paired, resulting in a diamagnetic solution (does not attract a magnetic field).

**Hint**: Think about how electron pairing affects magnetic properties of a substance.

6. **Conclusion**:
- Based on the observations, we can summarize:
- Dilute solutions are blue due to solvated electrons.
- Concentrated solutions are bronze due to clusters of metal ions.
- Blue solutions are paramagnetic, while bronze solutions are diamagnetic.

**Hint**: Summarize the key points to identify the correct statements regarding the behavior of alkali metals in liquid NH3.

### Final Answer
From the analysis, all the statements provided in the options are correct. Therefore, the correct choice is:
- **All the facts given above are found** (Option 4).