Question

Select the correct statements for [Fe(CN)\(_6\)]\(^{3-}\) complex:
(A) Paramagnetic
(B) sp\(^3\)d\(^2\) hybridization
(C) Magnetic moment = 5.92 BM
(D) d\(^2\)sp\(^3\) hybridization

• A. (A) and (D) only
• B. (A), (B) and (C) only
• C. (B), (C) and (D) only
• D. (B), (C) and (D) only

Hint:

In coordination complexes, the type of hybridization and magnetic moment depend on the nature of the ligands. Strong field ligands like cyanide lead to low-spin complexes and d\(^2\)sp\(^3\) hybridization.

Answer 1

The Correct Option is C

For the complex \([Fe(CN)_6]^{3-}\), let's evaluate each statement:
Step 1: Paramagnetism (A)
The iron ion in \([Fe(CN)_6]^{3-}\) is in the +3 oxidation state, so the electron configuration for Fe\(^{3+}\) is \( [Ar] \, 3d^5 \). Since it has unpaired electrons, this complex is paramagnetic. However, we need to focus on the hybridization and magnetic moment to determine the final correct answer.
Step 2: Hybridization (B) and (D)
In this complex, cyanide is a strong field ligand and causes a large splitting of the d-orbitals. Therefore, iron undergoes sp\(^3\)d\(^2\) hybridization and also forms a stable low-spin complex, making the hybridization d\(^2\)sp\(^3\).
Step 3: Magnetic Moment (C)
The magnetic moment is given as 5.92 BM, which is consistent with a low-spin octahedral complex with a d\(^5\) electron configuration. The formula to calculate magnetic moment is: \[ \mu = \sqrt{n(n+2)} \] where \(n = 5\) for d\(^5\) configuration. This gives a magnetic moment of 5.92 BM. Conclusion:
The correct statements are:
- (B) sp\(^3\)d\(^2\) hybridization
- (C) Magnetic moment = 5.92 BM
- (D) d\(^2\)sp\(^3\) hybridization
Thus, the correct answer is:
(3) (B), (C) and (D) only.
Final Answer: \[ \boxed{\text{The correct answer is (B), (C), and (D) only.}} \]