Which of the following ligands are correctly represented in an spectrochemical series ? .

Options

A. a.`SCN^(Θ), F^(Θ),CN^(Θ) `
B. b.`SCN^(Θ),CN^(Θ),F^(Θ)`
C. c.`F^(Θ),SCN^(Θ),CN^(Θ)`
D. d.`F^(Θ),CN^(Θ),SCN^(Θ)`

Answer

To determine which ligands are correctly represented in a spectrochemical series, we need to understand the concept of the spectrochemical series itself. Here’s a step-by-step solution:

### Step 1: Understand the Spectrochemical Series
The spectrochemical series is a list that ranks ligands based on their ability to split the d-orbitals of transition metal ions. Ligands that cause a small splitting are considered weak field ligands, while those that cause a large splitting are strong field ligands.

### Step 2: Identify the Ligands
In the question, we have the following ligands to analyze:
- SCN⁻ (thiocyanate)
- F⁻ (fluoride)
- CN⁻ (cyanide)

### Step 3: Rank the Ligands
According to the spectrochemical series, ligands can be ranked as follows (from weak field to strong field):
1. I⁻
2. Br⁻
3. SCN⁻
4. Cl⁻
5. S²⁻
6. NO₃⁻
7. F⁻
8. OH⁻
9. C₂O₄²⁻
10. O²⁻
11. H₂O
12. NCS⁻
13. EDTA
14. NH₃
15. EN (ethylenediamine)
16. Dipyridine
17. O-phen
18. NO₂⁻
19. CN⁻
20. CO

From this series, we can see that:
- SCN⁻ is a weak field ligand.
- F⁻ is also a weak field ligand but stronger than SCN⁻.
- CN⁻ is a strong field ligand.

### Step 4: Conclusion
Based on the ranking:
- CN⁻ has the highest field strength (strong field).
- F⁻ has a moderate field strength.
- SCN⁻ has the lowest field strength (weak field).

Thus, the correct order of the ligands in the spectrochemical series is:
**CN⁻ > F⁻ > SCN⁻**

### Final Answer
The correct representation in the spectrochemical series is:
- CN⁻ (strong field) > F⁻ (moderate field) > SCN⁻ (weak field).

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