In the complex `[Pt(py)_4][PtCl_4]`, the oxidation numbers of `Pt` atom in former and latter part of the compund are respectively

Options

A. (a) 0 and 0
B. (b) `+4` and `+2`
C. (c) `+2` and `+2`
D. (d) `0` and `+4`

Explanation

To determine the oxidation numbers of the platinum (Pt) atom in the complex `[Pt(py)_4][PtCl_4]`, we will analyze both parts of the compound separately.

### Step 1: Analyze the cationic part `[Pt(py)_4]`
1. The cationic part of the complex is `[Pt(py)_4]`.
2. In this complex, `py` (pyridine) is a neutral ligand, meaning it does not contribute any charge.
3. Let the oxidation number of platinum in this part be \( x \).
4. Since there are four neutral ligands (py), the total charge contributed by the ligands is \( 0 \).
5. Therefore, the overall charge of the cation is equal to the oxidation state of platinum:
\[ x + 0 = +1 \quad \text{(since the overall charge of the cation is +1)} \]
6. Thus, the oxidation number of Pt in `[Pt(py)_4]` is:
\[ x = +1 \]

### Step 2: Analyze the anionic part `[PtCl_4]`
1. The anionic part of the complex is `[PtCl_4]`.
2. Each chloride ion (Cl) has a charge of -1. Therefore, with four chloride ions, the total charge contributed by the ligands is \( 4 \times (-1) = -4 \).
3. Let the oxidation number of platinum in this part be \( y \).
4. The overall charge of the anion must equal the sum of the oxidation state of platinum and the charges from the chloride ions:
\[ y + (-4) = -1 \quad \text{(since the overall charge of the anion is -1)} \]
5. Rearranging gives:
\[ y - 4 = -1 \implies y = +3 \]
6. Thus, the oxidation number of Pt in `[PtCl_4]` is:
\[ y = +3 \]

### Final Answer
The oxidation numbers of the platinum atom in `[Pt(py)_4]` and `[PtCl_4]` are respectively:
- In `[Pt(py)_4]`: +1
- In `[PtCl_4]`: +3