JEE Main 2018 — Coordination Compounds Question with Solution
From: JEE Main 2018 (Online) 15th April Morning Slot
Question
The correct combination is :
Choose an option
Show full solutionCorrect option: B
Correct answer
B[Ni(Cl)4]2- paramagnetic ;
[Ni(CO)4] tetrahedral
[Ni(CO)4] tetrahedral
Step-by-step explanation
[NiCl4]2– : Oxidation state of Ni in [NiCl4]2– = + 2
Cl– is a weak field ligand and cannot take part in pairing of electrons.
Hence, the complex is tetrahedral and paramagnetic with two unpaired electrons.
[Ni(CO)4] : Oxidation state of Ni in [Ni(CO)4] is zero. CO is a strong field ligand thus pairing of electrons takes place in d-orbitals.
Hence, the complex is tetrahedral and diamagnetic.
Cl– is a weak field ligand and cannot take part in pairing of electrons.
Hence, the complex is tetrahedral and paramagnetic with two unpaired electrons.
[Ni(CO)4] : Oxidation state of Ni in [Ni(CO)4] is zero. CO is a strong field ligand thus pairing of electrons takes place in d-orbitals.
Hence, the complex is tetrahedral and diamagnetic.
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This is a previous-year question from JEE Main 2018, covering the Coordination Compounds chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.