Which of the following complex compound is ''Pentaaquacyanidoiron (III) trichloridotricyanido cobaltate (III) '' ?

Options

A. `[Fe(CN)(H_2O)_5][CoCl_3(CN)_3]`
B. `[Fe(CN)(H_2O)_5][CoCl_3(CN)_3]_3`
C. `[Fe(CN)(H_2O)_4]_3[CoCl_3(CN)_3]_2`
D. `[Fe(CN)(H_2O)_5]_3[CoCl_3(CN)_3]_2`

Answer

To determine which complex compound corresponds to "Pentaaquacyanidoiron (III) trichloridotricyanidocobaltate (III)," we will analyze the components of the name and the oxidation states involved.

### Step-by-Step Solution:

1. **Understanding the Name**:
- "Pentaaqua" indicates that there are 5 water molecules (H2O).
- "Cyanido" refers to cyanide ions (CN^-).
- "Iron (III)" indicates that iron (Fe) has an oxidation state of +3.
- "Trichlorido" means there are 3 chloride ions (Cl^-).
- "Tricyanido" indicates there are 3 cyanide ions (CN^-).
- "Cobaltate (III)" indicates that cobalt (Co) also has an oxidation state of +3.

2. **Constructing the Complex**:
- The complex can be written as:
\[ [Fe(CN)_{5}(H_2O)_{5}][CoCl_{3}(CN)_{3}] \]
- Here, we have 5 water molecules coordinated to iron, 3 chloride ions, and 3 cyanide ions coordinated to cobalt.

3. **Assigning Oxidation States**:
- For Iron (Fe):
- Oxidation state = +3 (as given).
- For Cobalt (Co):
- Oxidation state = +3 (as given).
- For Cyanide (CN^-):
- Each cyanide has an oxidation state of -1.
- For Chloride (Cl^-):
- Each chloride has an oxidation state of -1.
- For Water (H2O):
- Each water molecule has an oxidation state of 0.

4. **Calculating the Overall Charge**:
- The total contribution from the ligands:
- From 5 H2O: \(5 \times 0 = 0\)
- From 3 Cl: \(3 \times (-1) = -3\)
- From 3 CN: \(3 \times (-1) = -3\)
- Total charge from ligands = \(0 - 3 - 3 = -6\)
- The overall charge of the complex must balance with the oxidation states of Fe and Co:
- Total charge = +3 (Fe) + +3 (Co) = +6

5. **Finalizing the Complex**:
- The complex can be represented as:
\[ [Fe(CN)_{5}(H_2O)_{5}][CoCl_{3}(CN)_{3}] \]
- The oxidation states of both iron and cobalt are +3, confirming the name given.

### Conclusion:
The complex compound "Pentaaquacyanidoiron (III) trichloridotricyanidocobaltate (III)" corresponds to the structure we derived, with both iron and cobalt in the +3 oxidation state.