Question

Match the LIST-I with LIST-II

Choose the correct answer from the options given below:

• A. A-I, B-II, C-III, D-IV
• B. A-III, B-II, C-I, D-IV
• C. A-III, B-IV, C-II, D-I
• D. A-IV, B-I, C-III, D-II

Hint:

- Strong field ligands (CO, CN⁻) cause pairing → low spin complexes - Weak field ligands (Cl⁻, Br⁻) don't cause pairing → high spin complexes - Magnetic moment (μ) = √[n(n+2)] BM, where n = unpaired electrons - Ni²⁺ (d⁸): tetrahedral/square planar; Mn²⁺ (d⁵): always high spin

Answer 1

The Correct Option is B

Correct Matching:
- A: [Ni(CO)₄] - III (Tetrahedral, 0 BM)

• CO is a strong field ligand → low spin complex
• d⁸ configuration → tetrahedral with paired electrons (μ = 0)

- B: [Ni(CN)₄]^2- - II (Square planar, 0 BM)

• CN^- is a strong field ligand → low spin
• d⁸ configuration → square planar with paired electrons (μ = 0)

- C: [NiCl₄]^2- - I (Tetrahedral, 2.8 BM)

• Cl^- is a weak field ligand → high spin
• d⁸ configuration → tetrahedral with 2 unpaired electrons (μ = √8 ≠ 2.8 BM)

- D: [MnBr₄]^2- - IV (Tetrahedral, 5.9 BM)

• Br^- is a weak field ligand → high spin
• d⁵ configuration → tetrahedral with 5 unpaired electrons (μ = √35 ≈ 5.9 BM)