JEE Main · 2019mediumCORD-078

Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II): (A) Co → (B) Zn → (C) Rh → (D) Mg…

Coordination Compounds · Class 12 · JEE Main Previous Year Question

Question

Match the metals (column I) with the coordination compound(s)/enzyme(s) (column II): (A) Co → (B) Zn → (C) Rh → (D) Mg (i) Wilkinson catalyst (ii) Chlorophyll (iii) Vitamin B₁₂ (iv) Carbonic anhydrase

Options
  1. a

    (A)-(iii); (B)-(iv); (C)-(i); (D)-(ii)

    ✓
  2. b

    (A)-(i); (B)-(ii); (C)-(iii); (D)-(iv)

  3. c

    (A)-(ii); (B)-(i); (C)-(iv); (D)-(iii)

  4. d

    (A)-(iv); (B)-(iii); (C)-(i); (D)-(ii)

Correct Answera

(A)-(iii); (B)-(iv); (C)-(i); (D)-(ii)

Detailed Solution

🧠 Four Bioinorganic Metals — Match Each

This is pure recall: each metal goes with one named compound or enzyme.

| Metal | Compound/Enzyme | |---|---| | Co | Vitamin B₁₂ (cobalamin) | | Zn | Carbonic anhydrase | | Rh | Wilkinson's catalyst | | Mg | Chlorophyll |

🗺️ Justify Each Pairing

  • Co → Vitamin B₁₂: cobalamin has Co at the centre of a corrin ring. Essential cofactor for methionine synthesis.
  • Zn → Carbonic anhydrase: Zn²⁺ in the active site activates water for CO2+H2O→HCO3−+H+\mathrm{CO_2 + H_2O \to HCO_3^- + H^+} chemistry.
  • Rh → Wilkinson catalyst: [(PPh3)3RhCl][(\mathrm{PPh_3})_3\mathrm{RhCl}] for olefin hydrogenation.
  • Mg → Chlorophyll: Mg²⁺ at the centre of a porphyrin ring; absorbs red and blue light, transmits green (hence plant colour).

So: A(Co)–(iii); B(Zn)–(iv); C(Rh)–(i); D(Mg)–(ii) — option (1).

⚡ The Bioinorganic Quartet

Memorise these four metal-bio pairings — they appear in every JEE/NEET coordination chapter:

Co→B12; Mg→chlorophyll; Fe→haemoglobin; Zn→CA & carboxypeptidase.\mathrm{Co \rightarrow B_{12};\ Mg \rightarrow chlorophyll;\ Fe \rightarrow haemoglobin;\ Zn \rightarrow CA \,\&\, carboxypeptidase}.

⚠️ Don't Swap Mg and Fe

Chlorophyll has Mg, not Fe. Haemoglobin has Fe, not Mg. Both are porphyrin systems — easy to confuse.

Answer: (1) A-(iii); B-(iv); C-(i); D-(ii)\boxed{\text{Answer: (1) A-(iii); B-(iv); C-(i); D-(ii)}}

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