Assertion: Oxidation state of Fe in `Fe(CO)_(5)` is zero.
Reason: Synergic bonding takes place in this metal carbonyl complex.

Options

A. If assertion is true but the reason is false
B. If assertion is false but reason is true
C. If both assertion and reason are true and the reason is the correct explanation of assertion
D. If both assertion and reason are true but reason is not the correct explanation of assertion

Answer

To solve the assertion and reasoning question regarding the oxidation state of iron in `Fe(CO)_(5)` and the concept of synergic bonding, we can break down the solution into a few steps:

### Step 1: Determine the oxidation state of Fe in `Fe(CO)_(5)`.
- The carbonyl (CO) is a neutral ligand, meaning it does not contribute to the oxidation state of the metal. Each CO molecule donates 2 electrons to the metal center but does not carry a charge.
- Since there are 5 CO ligands, the total contribution to the electron count from the ligands is 5 × 0 = 0.
- The oxidation state of iron (Fe) can be calculated using the formula:
\[ \text{Oxidation state of Fe} + \text{Sum of oxidation states of ligands} = \text{Overall charge of the complex} \]
For `Fe(CO)_(5)`, the overall charge is 0 (since it is a neutral complex).
\[ \text{Oxidation state of Fe} + 0 = 0 \]
Therefore, the oxidation state of Fe is 0.

### Step 2: Understand the concept of synergic bonding.
- Synergic bonding, also known as back-bonding, occurs when the metal donates electrons to the ligand (in this case, CO) and the ligand, in return, donates some of its electron density back to the metal.
- In `Fe(CO)_(5)`, the CO ligands donate a lone pair of electrons to form sigma bonds with Fe. The empty π* (pi star) orbitals of CO can accept electron density from the filled d-orbitals of Fe, forming π back-bonds.
- This interaction stabilizes the complex and is a characteristic feature of metal-carbonyl complexes.

### Step 3: Evaluate the assertion and reason.
- **Assertion**: The oxidation state of Fe in `Fe(CO)_(5)` is zero. (True)
- **Reason**: Synergic bonding takes place in this metal carbonyl complex. (True)
- However, while both statements are true, the reason does not explain the assertion. The oxidation state of Fe being zero is due to the neutral nature of the CO ligands, not directly due to synergic bonding.

### Conclusion:
- The assertion is true, and the reason is also true, but the reason is not the correct explanation for the assertion.

### Final Answer:
- Assertion: True
- Reason: True, but does not explain the assertion.