In which of the following pair oxidation number of Fe is same :-

Options

A. `K_(3)Fe(CN)_(6),Fe_(2)O_(3)`
B. `Fe(CO)_(5),Fe_(2)O_(3)`
C. `Fe_(2)O_(3),FeO`
D. `Fe_(2)(SO_(4))_(3),K_(4)Fe(CN)_(6)`

Answer

To determine the pairs in which the oxidation number of Fe is the same, we will analyze each compound given in the options step by step.

### Step-by-Step Solution:

1. **Identify the first pair: K₃Fe(CN)₆ and Fe₂O₃**
- For K₃Fe(CN)₆:
- Potassium (K) has an oxidation state of +1.
- Cyanide (CN) has a charge of -1.
- Let the oxidation state of Fe be \( X \).
- The total charge of the compound is 0.
- Therefore, the equation is:
\[ 3(+1) + X + 6(-1) = 0 \]
Simplifying gives:
\[ 3 + X - 6 = 0 \implies X - 3 = 0 \implies X = +3 \]
- For Fe₂O₃:
- Let the oxidation state of Fe be \( X \).
- Oxygen (O) has an oxidation state of -2.
- The total charge of the compound is 0.
- Therefore, the equation is:
\[ 2X + 3(-2) = 0 \]
Simplifying gives:
\[ 2X - 6 = 0 \implies 2X = 6 \implies X = +3 \]
- **Conclusion**: In both K₃Fe(CN)₆ and Fe₂O₃, the oxidation state of Fe is +3.

2. **Identify the second pair: Fe(CO)₅ and Fe₂O₃**
- For Fe(CO)₅:
- Carbon monoxide (CO) is a neutral ligand (0 charge).
- Let the oxidation state of Fe be \( X \).
- Therefore, the equation is:
\[ X + 5(0) = 0 \implies X = 0 \]
- For Fe₂O₃, we already calculated that the oxidation state of Fe is +3.
- **Conclusion**: The oxidation states are different (+0 for Fe(CO)₅ and +3 for Fe₂O₃).

3. **Identify the third pair: Fe₂O₃ and FeO**
- For FeO:
- Let the oxidation state of Fe be \( X \).
- Oxygen has an oxidation state of -2.
- Therefore, the equation is:
\[ X + (-2) = 0 \implies X = +2 \]
- For Fe₂O₃, we already calculated that the oxidation state of Fe is +3.
- **Conclusion**: The oxidation states are different (+3 for Fe₂O₃ and +2 for FeO).

4. **Identify the fourth pair: Fe₂(SO₄)₃ and K₄Fe(CN)₆**
- For Fe₂(SO₄)₃:
- Let the oxidation state of Fe be \( X \).
- The sulfate ion (SO₄) has a charge of -2.
- Therefore, the equation is:
\[ 2X + 3(-2) = 0 \implies 2X - 6 = 0 \implies 2X = 6 \implies X = +3 \]
- For K₄Fe(CN)₆:
- We already calculated that the oxidation state of Fe is +3.
- **Conclusion**: In both Fe₂(SO₄)₃ and K₄Fe(CN)₆, the oxidation state of Fe is +3.

### Final Conclusion:
The pairs in which the oxidation number of Fe is the same are:
- K₃Fe(CN)₆ and Fe₂O₃ (both +3)
- Fe₂(SO₄)₃ and K₄Fe(CN)₆ (both +3)