In which of the following compounds, the oxidation state of transition metal is zero ?

Options

A. `CrO_(5)`
B. `4//5`
C. `FeSO_(4)`
D. `Fe(CO)_(5)`

Explanation

To determine the oxidation state of the transition metal in the given compounds, we need to analyze each option carefully.

**Step 1: Analyze each option.**

1. **Option A**: This option does not contain a transition metal, so we can eliminate it immediately.

2. **Option B**: Similar to option A, this option also does not contain a transition metal, so it can be eliminated as well.

3. **Option C**: This option contains Fe in FeSO4. To find the oxidation state of Fe, we need to consider the sulfate ion (SO4^2-), which has an oxidation state of -2. The overall charge of the compound is neutral (0), so we can set up the equation:
\[ \text{Oxidation state of Fe} + \text{Oxidation state of SO4} = 0 \]
\[ x + (-2) = 0 \implies x = +2 \]
Therefore, the oxidation state of Fe in FeSO4 is +2, not zero.

4. **Option D**: This option contains Fe in Fe(CO)5. Carbon monoxide (CO) is a neutral ligand, meaning it does not contribute any charge to the complex. Therefore, the oxidation state of Fe can be calculated as follows:
\[ \text{Oxidation state of Fe} + \text{Oxidation state of CO} = 0 \]
Since CO is neutral, we have:
\[ x + 0 = 0 \implies x = 0 \]
Thus, the oxidation state of Fe in Fe(CO)5 is 0.

**Step 2: Conclusion**

From our analysis, the only compound where the oxidation state of the transition metal (Fe) is zero is **Fe(CO)5**.

**Final Answer**: The oxidation state of the transition metal is zero in **Fe(CO)5**.

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