The complex compound in which metal is not present in zero oxidation state?

Options

A. `Mn_(2)(CO)_(10)`
B. `[Ni(CO)_(4)]`
C. `[cr(C_(6)H_(6))_(2)]`
D. `K[PtCI_(3)(C_(2)H_(4))]`

Answer

To solve the question regarding the complex compound in which the metal is not present in zero oxidation state, we will analyze each of the given complexes step by step.

### Step 1: Analyze the first complex - Mn(CO)₁₀
1. **Identify the ligands**: CO (carbon monoxide) is a neutral ligand.
2. **Set up the equation**: Let the oxidation state of manganese (Mn) be \( x \). The overall charge of the complex is 0.
\[ x + 10(0) = 0 \implies x = 0 \]
3. **Conclusion**: Manganese is in the zero oxidation state.

### Step 2: Analyze the second complex - Ni(CO)₄
1. **Identify the ligands**: CO is again a neutral ligand.
2. **Set up the equation**: Let the oxidation state of nickel (Ni) be \( x \). The overall charge of the complex is 0.
\[ x + 4(0) = 0 \implies x = 0 \]
3. **Conclusion**: Nickel is in the zero oxidation state.

### Step 3: Analyze the third complex - Cr(C₆H₆)₂
1. **Identify the ligands**: C₆H₆ (benzene) is a neutral ligand.
2. **Set up the equation**: Let the oxidation state of chromium (Cr) be \( x \). The overall charge of the complex is 0.
\[ x + 2(0) = 0 \implies x = 0 \]
3. **Conclusion**: Chromium is in the zero oxidation state.

### Step 4: Analyze the fourth complex - K[PtCl₃(C₂H₄)]
1. **Identify the ligands**: Cl (chloride) is a negative ligand, and C₂H₄ (ethylene) is a neutral ligand.
2. **Set up the equation**: Let the oxidation state of platinum (Pt) be \( x \). The overall charge of the complex is -1 (since K is +1).
\[ x + 3(-1) + 0 = -1 \]
Simplifying this gives:
\[ x - 3 = -1 \implies x = +2 \]
3. **Conclusion**: Platinum is in the +2 oxidation state.

### Final Conclusion:
Among the complexes analyzed, the only metal that is not in the zero oxidation state is platinum (Pt) in the complex K[PtCl₃(C₂H₄)], which is in the +2 oxidation state.

Thus, the answer to the question is:
**The complex compound in which metal is not present in zero oxidation state is K[PtCl₃(C₂H₄)].**