The incorrect statement among the following is :

Options

A. The colour of `[Ni(H_(2)O)_(6)]^(2+)` changes on adding ethylene diamine.
B. Crystal field theory consider the covalent character of bonding between ligand and central atoms.
C. The magnitude of CFSE of octahedral complexes is higher than that of corresponding tetrahedral complexes.
D. `[Co(C_(2)O_(4))_(3)]^(3-)` does not contains unpaired electrons.

Answer

To solve the question regarding the incorrect statement among the given options, we will analyze each statement step by step.

### Step 1: Analyze the first statement
**Statement:** The color of Ni(H2O)6^2+ changes on adding ethylenediamine.

**Analysis:**
- Ni(H2O)6^2+ is an octahedral complex where water acts as a ligand.
- When ethylenediamine (en), a stronger ligand, is added, it replaces water molecules.
- Stronger ligands cause greater splitting of d-orbitals, which can lead to a change in color due to the absorption of different wavelengths of light.
- **Conclusion:** This statement is **correct**.

### Step 2: Analyze the second statement
**Statement:** Crystal field theory considers the covalent character of bonding between ligand and center atom.

**Analysis:**
- Crystal Field Theory (CFT) primarily describes the interaction between the central metal ion and the surrounding ligands as an electrostatic interaction.
- It does not account for covalent character; rather, it assumes ionic bonding.
- **Conclusion:** This statement is **incorrect**.

### Step 3: Analyze the third statement
**Statement:** The magnitude of CFSE (Crystal Field Stabilization Energy) of an octahedral complex is higher than that of the corresponding tetrahedral complex.

**Analysis:**
- In octahedral complexes, the ligands are positioned to create a larger splitting of d-orbitals compared to tetrahedral complexes.
- Therefore, the CFSE is indeed higher for octahedral complexes than for tetrahedral ones.
- **Conclusion:** This statement is **correct**.

### Step 4: Analyze the fourth statement
**Statement:** Co(C2O4)3^3- does not contain unpaired electrons.

**Analysis:**
- Cobalt in Co(C2O4)3^3- is in the +3 oxidation state, giving it a 3d^6 configuration.
- Oxalate (C2O4^2-) is a strong field ligand and leads to pairing of electrons in the d-orbitals.
- In a strong field, all six electrons will pair up, resulting in no unpaired electrons.
- **Conclusion:** This statement is **correct**.

### Final Conclusion
The incorrect statement among the options is the **second statement**, which claims that crystal field theory considers the covalent character of bonding between ligand and center atom.

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