In Which of the following compunds the metal is in the lowest oxidation state?

Options

A. `[Co(NH_(3))_(5)Br]SO_(4)`
B. `Fe_(3)[Fe(CN)_(6)]_(2)`
C. `[Mn_(2)(CO)_(10)]`
D. `K[PtCI_(3)(C_(2)H_(4))]`

Answer

To determine which of the given compounds has the metal in the lowest oxidation state, we will analyze each compound step by step.

### Step 1: Analyze the first compound (Cobalt complex)
- **Compound**: Cobalt complex (let's assume it's [Co(NH3)3Br])
- **Oxidation State Calculation**:
- Let the oxidation state of cobalt be \( X \).
- NH3 is a neutral ligand (0 oxidation state).
- Br is a negative ligand with an oxidation state of -1.
- The overall charge of the complex is 0.

The equation becomes:
\[ X + 0 + (-1) = 0 \implies X - 1 = 0 \implies X = +1 \]

### Step 2: Analyze the second compound (Iron complex)
- **Compound**: Iron complex (assumed to be [Fe(CN)6]3-)
- **Oxidation State Calculation**:
- Let the oxidation state of iron be \( X \).
- CN is a negative ligand with an oxidation state of -1.
- The complex has a charge of -3.

The equation becomes:
\[ X + (-1) \times 6 = -3 \implies X - 6 = -3 \implies X = +3 \]

### Step 3: Analyze the third compound (Manganese complex)
- **Compound**: Manganese complex (Mn2CO10)
- **Oxidation State Calculation**:
- Let the oxidation state of manganese be \( X \).
- CO is a neutral ligand (0 oxidation state).

The equation becomes:
\[ 2X + 0 = 0 \implies 2X = 0 \implies X = 0 \]

### Step 4: Analyze the fourth compound (Potassium complex)
- **Compound**: Potassium complex (assumed to be K[Co(C2H4)Cl3])
- **Oxidation State Calculation**:
- Let the oxidation state of cobalt be \( X \).
- K has an oxidation state of +1.
- Cl is a negative ligand with an oxidation state of -1.
- C2H4 is a neutral ligand (0 oxidation state).
- The overall charge of the complex is 0.

The equation becomes:
\[ 1 + X + (-1) \times 3 + 0 = 0 \implies 1 + X - 3 = 0 \implies X - 2 = 0 \implies X = +2 \]

### Conclusion
Now we summarize the oxidation states:
- Cobalt complex: +1
- Iron complex: +3
- Manganese complex: 0
- Potassium complex: +2

The lowest oxidation state among these is **0** from the manganese complex (Mn2CO10).

### Final Answer
The metal is in the lowest oxidation state in the compound **Mn2CO10**.