JEE Main · 2025 · Shift-IIhardCORD-255

Match the LIST-I with LIST-II | LIST-I (Complex/Species) | LIST-II (Shape & magnetic moment) | |---|---| | A. [Ni(CO)4]…

Coordination Compounds · Class 12 · JEE Main Previous Year Question

Question

Match the LIST-I with LIST-II | LIST-I (Complex/Species) | LIST-II (Shape & magnetic moment) | |---|---| | A. [\ceNi(CO)4][\ce{Ni(CO)4}] | I. Tetrahedral, 2.8 BM | | B. [\ceNi(CN)4]2−[\ce{Ni(CN)4}]^{2-} | II. Square planar, 0 BM | | C. [\ceNiCl4]2−[\ce{NiCl4}]^{2-} | III. Tetrahedral, 0 BM | | D. [\ceMnBr4]2−[\ce{MnBr4}]^{2-} | IV. Tetrahedral, 5.9 BM |

Choose the correct answer from the options given below:

Options
  1. a

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

  2. b

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

  3. c

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

    ✓
  4. d

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

Correct Answerc

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

Detailed Solution

🧠 Match Geometry + μ for Each Ni Complex

🗺️ Evaluate Each

| Complex | Metal/d-config | Ligand strength | Geometry | Unpaired | μ | |---|---|---|---|---|---| | A: [Ni(CO)4][\mathrm{Ni(CO)_4}] | Ni(0) d¹⁰ | strong (CO) | Td | 0 | 0 BM | | B: [Ni(CN)4]2−[\mathrm{Ni(CN)_4}]^{2-} | Ni(II) d⁸ | strong (CN⁻) | sq pl | 0 | 0 BM | | C: [NiCl4]2−[\mathrm{NiCl_4}]^{2-} | Ni(II) d⁸ | weak (Cl⁻) | Td | 2 | 2.83 BM | | D: [MnBr4]2−[\mathrm{MnBr_4}]^{2-} | Mn(II) d⁵ | weak (Br⁻) | Td | 5 | 5.92 BM |

🗺️ Match List-II

| Complex | (Geometry, μ) | List-II label | |---|---|---| | A: Ni(CO)₄ | Td, 0 BM | III | | B: Ni(CN)₄²⁻ | sq pl, 0 BM | II | | C: NiCl₄²⁻ | Td, ~2.8 BM | I | | D: MnBr₄²⁻ | Td, 5.9 BM | IV |

So: A-III, B-II, C-I, D-IV.

⚡ Ni(II) Geometry by Ligand Strength

| Ligand | Geometry | |---|---| | Strong (CN⁻, CO) | Sq pl, diamagnetic | | Weak (Cl⁻, Br⁻, F⁻) | Td, paramagnetic (2 unpaired) | | Moderate (H₂O, NH₃) | Octahedral (with 2 extra ligands), paramagnetic |

⚠️ Ni(0) is d¹⁰, Always Diamagnetic

[Ni(CO)4][\mathrm{Ni(CO)_4}] has Ni(0) d¹⁰ — fully filled, μ = 0 regardless of geometry.

Answer: (3) A-III, B-II, C-I, D-IV\boxed{\text{Answer: (3) A-III, B-II, C-I, D-IV}}

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