A solution of `[Ni(H_(2)O)_(6)]^(2+)` is green but a solution of `[Ni(CN)_(4)]^(2-)` is colourless Explain.

Explanation

To explain why a solution of \([Ni(H_2O)_6]^{2+}\) is green while a solution of \([Ni(CN)_4]^{2-}\) is colorless, we need to consider the nature of the ligands involved and the electronic transitions that occur in these complexes.

### Step-by-Step Solution:

1. **Identify the Complexes**:
- The first complex is \([Ni(H_2O)_6]^{2+}\), where nickel is in the +2 oxidation state and coordinated with six water molecules.
- The second complex is \([Ni(CN)_4]^{2-}\), where nickel is also in the +2 oxidation state but coordinated with four cyanide ions.

...