In the complexes `[Fe(CN)_(6)]^(3-)and[Pt(en)(H_(2)O)_(2)(NO_(2))(Cl)]^(2+)` the respective oxidation numbers of central metal atoms are :

Options

A. `+3and+4`
B. `+6and+4`
C. `+6and+3`
D. `+3and+3`

Answer

To find the oxidation numbers of the central metal atoms in the complexes \([Fe(CN)_6]^{3-}\) and \([Pt(en)(H_2O)_2(NO_2)(Cl)]^{2+}\), we can follow these steps:

### Step 1: Determine the oxidation state of Iron in \([Fe(CN)_6]^{3-}\)

1. Let the oxidation state of Iron (Fe) be \(X\).
2. The cyanide ion (CN) has an oxidation number of \(-1\).
3. Since there are 6 CN ligands, the total contribution from CN is \(6 \times (-1) = -6\).
4. The overall charge of the complex is \(-3\).

Now we can set up the equation:
\[ X + (-6) = -3 \]
\[ X - 6 = -3 \]
\[ X = -3 + 6 \]
\[ X = +3 \]

### Step 2: Determine the oxidation state of Platinum in \([Pt(en)(H_2O)_2(NO_2)(Cl)]^{2+}\)

1. Let the oxidation state of Platinum (Pt) be \(Y\).
2. The ethylenediamine (en) and water (H2O) are neutral ligands, contributing \(0\) to the oxidation state.
3. The nitro group (NO2) has an oxidation number of \(-1\).
4. The chloride ion (Cl) also has an oxidation number of \(-1\).
5. The overall charge of the complex is \(+2\).

Now we can set up the equation:
\[ Y + 0 + 0 + (-1) + (-1) = +2 \]
\[ Y - 2 = +2 \]
\[ Y = +2 + 2 \]
\[ Y = +4 \]

### Conclusion

- The oxidation state of Iron (Fe) in \([Fe(CN)_6]^{3-}\) is \(+3\).
- The oxidation state of Platinum (Pt) in \([Pt(en)(H_2O)_2(NO_2)(Cl)]^{2+}\) is \(+4\).

### Summary of the Answer:
- Oxidation state of Fe: \(+3\)
- Oxidation state of Pt: \(+4\)