Which of the following statement are incorrect ?

Options

A. If `Delta_(0) lt P `, high spin state in more stable
B. `NO_(2)` is a very strong ligand
C. Colour of a complex depends upon nature of metal ion only
D. `Delta_(0) gt Delta_(t)`

Answer

To determine which of the statements are incorrect, we will analyze each statement one by one based on our knowledge of coordination compounds and crystal field theory.

### Step-by-Step Solution:

1. **Statement 1: If ΔO is lesser than P (pairing energy), high spin state is more stable.**
- **Analysis:** In octahedral complexes, when the crystal field splitting energy (ΔO) is less than the pairing energy (P), electrons will occupy the higher energy orbitals rather than pairing up in the lower energy orbitals. This leads to a high spin configuration, which is indeed more stable under these conditions.
- **Conclusion:** This statement is **true**.

2. **Statement 2: NO2 is a very strong ligand.**
- **Analysis:** The strength of ligands is often assessed using the spectrochemical series. NO2 is classified as a strong field ligand, but it is not the strongest. Strong ligands include CN⁻ and CO, while NO2 is weaker than these. However, it is still considered a strong ligand compared to many others.
- **Conclusion:** This statement is **true**.

3. **Statement 3: The color of a complex depends upon the nature of the metal ion only.**
- **Analysis:** The color of a coordination complex arises from d-d transitions and charge transfer processes, which involve both the metal ion and the ligands. Therefore, the color is influenced by the nature of both the metal ion and the ligands surrounding it.
- **Conclusion:** This statement is **false**.

4. **Statement 4: ΔO is greater than ΔT.**
- **Analysis:** In coordination chemistry, the crystal field splitting energy (ΔO) for octahedral complexes is indeed greater than that for tetrahedral complexes (ΔT). Specifically, ΔT is approximately 4/9 of ΔO.
- **Conclusion:** This statement is **true**.

### Final Answer:
The incorrect statement is **Statement 3**: "The color of a complex depends upon the nature of the metal ion only."

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