On addition of metal ions, colour of liquid `NH_(3)`solutions converts into bronze, the reason is:-

Options

A. Ammoniated electrons
B. Metal amide formation
C. Liberation of `NH_(3)` gas
D. Cluster formation of metal ions

Explanation

To solve the question regarding the color change of liquid ammonia (NH₃) solutions upon the addition of metal ions, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ammonia (NH₃)**:
- Ammonia is a colorless gas with a pungent smell. When dissolved in water, it forms a basic solution.

**Hint**: Remember that ammonia can act as a ligand, coordinating with metal ions.

2. **Addition of Metal Ions**:
- When metal ions are added to the ammonia solution, they interact with the ammonia molecules.

**Hint**: Consider how metal ions can influence the properties of the solution they are added to.

3. **Formation of Ionic Clusters**:
- The metal ions can form complexes with ammonia, leading to the formation of ionic clusters. This complexation can alter the electronic environment around the metal ions.

**Hint**: Think about how the coordination of ligands can change the color of metal complexes.

4. **Color Change to Bronze**:
- The interaction between the metal ions and ammonia results in a change in the absorption of light, leading to the observed color change to bronze. This is due to the d-d transitions in the metal ions, which occur when they are surrounded by ligands like ammonia.

**Hint**: Recall that the color of a solution can be a result of specific electronic transitions within the metal ions.

5. **Conclusion**:
- Therefore, the color change to bronze is attributed to the formation of these metal-ammonia complexes, which modify the light absorption characteristics of the solution.

### Final Answer:
The color of liquid NH₃ solutions changes to bronze upon the addition of metal ions due to the formation of ionic clusters and the resulting electronic transitions in the metal complexes.