The compound in which oxidation state of metal is zero-

Options

A. `Fe_(2)(CO)_(9)`
B. `Ni(CO)_(4)`
C. `Fe_(3)(CO)_(9)`
D. All the above

Answer

To determine the compound in which the oxidation state of the metal is zero, we can analyze the options provided in the question. Let's break down the steps to find the solution:

### Step-by-Step Solution:

1. **Understanding Oxidation States**:
- The oxidation state of an element in a compound is a measure of the degree of oxidation (loss of electrons) of that element. An oxidation state of zero indicates that the element is in its elemental form.

2. **Identifying the Metal**:
- We need to identify the metal in the compound and determine its oxidation state. The oxidation state of a metal can be influenced by the ligands or other atoms it is bonded to.

3. **Analyzing the Options**:
- Let's consider a compound where the metal is bonded to carbon monoxide (CO). Carbon monoxide is a neutral ligand, meaning it does not contribute any charge to the overall oxidation state of the metal.

4. **Setting Up the Equation**:
- If we denote the oxidation state of the metal as \( x \) and since CO is neutral, we can write the equation for the total charge of the compound:
\[ x + 0 = 0 \]
- This indicates that the oxidation state of the metal must be zero.

5. **Conclusion**:
- Therefore, in a compound where the metal is bonded to carbon monoxide, the oxidation state of the metal is zero. This is true for other neutral ligands as well, but in this case, we specifically looked at CO.

### Final Answer:
The compound in which the oxidation state of the metal is zero is one that contains carbon monoxide (CO) as a ligand.

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