`MnO_(4)^(-)` is of intense pink colour, though `Mn` is in`(+7)` oxidation state.It is due to:

Answer

To understand why the permanganate ion \( \text{MnO}_4^{-} \) is of intense pink color despite manganese being in the +7 oxidation state, we can break down the explanation into several steps:

### Step 1: Identify the oxidation state of manganese in \( \text{MnO}_4^{-} \)
In the permanganate ion \( \text{MnO}_4^{-} \), manganese (Mn) is in the +7 oxidation state. This can be determined from the overall charge of the ion and the known oxidation states of oxygen, which is typically -2.

### Step 2: Determine the electronic configuration of \( \text{Mn}^{+7} \)
The electronic configuration of manganese in the +7 oxidation state is \( \text{[Ar]} 3d^0 \). This indicates that there are no electrons in the 3d subshell, meaning there are no unpaired electrons.

### Step 3: Understand the implications of having no unpaired electrons
Since \( \text{Mn}^{+7} \) has no unpaired electrons, it cannot undergo d-d transitions, which are typically responsible for the absorption of visible light and the appearance of color in transition metal complexes.

### Step 4: Explore the concept of charge transfer
Although \( \text{Mn}^{+7} \) has no unpaired electrons, the intense pink color of \( \text{MnO}_4^{-} \) arises from a phenomenon known as charge transfer. In this case, oxygen donates an electron to manganese, effectively reducing it from \( \text{Mn}^{+7} \) to \( \text{Mn}^{+6} \).

### Step 5: Identify the electronic configuration of \( \text{Mn}^{+6} \)
The electronic configuration of \( \text{Mn}^{+6} \) is \( \text{[Ar]} 3d^5 \). In this state, there is one unpaired electron in the 3d subshell.

### Step 6: Relate the presence of unpaired electrons to color
The presence of one unpaired electron in \( \text{Mn}^{+6} \) allows for d-d transitions, which can absorb certain wavelengths of light. This absorption results in the intense pink color observed in the permanganate ion.

### Conclusion
The intense pink color of \( \text{MnO}_4^{-} \) is due to charge transfer from oxygen to manganese, leading to the formation of \( \text{Mn}^{+6} \), which has unpaired electrons that can participate in electronic transitions.