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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 4 April 2025, Shift 2, Chemistry Q60

Question 60 of 75 in this shift, Chemistry question 10 of 25, Section A.

The correct order of [FeF6]3−\mathrm{[FeF_6]^{3-}}, [CoF6]3−\mathrm{[CoF_6]^{3-}}, [Ni(CO)4]\mathrm{[Ni(CO)_4]} and [Ni(CN)4]2−\mathrm{[Ni(CN)_4]^{2-}} complex species based on the number of unpaired electrons present is :
  1. (1)[FeF6]3−>[CoF6]3−>[Ni(CN)4]2−>[Ni(CO)4]\mathrm{[FeF_6]^{3-}>[CoF_6]^{3-}>[Ni(CN)_4]^{2-}>[Ni(CO)_4]}
  2. (2)[CoF6]3−>[FeF6]3−>[Ni(CO)4]>[Ni(CN)4]2−\mathrm{[CoF_6]^{3-}>[FeF_6]^{3-}>[Ni(CO)_4]>[Ni(CN)_4]^{2-}}
  3. (3)[FeF6]3−>[CoF6]3−>[Ni(CN)4]2−=[Ni(CO)4]\mathrm{[FeF_6]^{3-}>[CoF_6]^{3-}>[Ni(CN)_4]^{2-}=[Ni(CO)_4]}Official answer
  4. (4)[Ni(CN)4]2−>[FeF6]3−>[CoF6]3−>[Ni(CO)4]\mathrm{[Ni(CN)_4]^{2-}>[FeF_6]^{3-}>[CoF_6]^{3-}>[Ni(CO)_4]}

Official answer

Option 3

NTA final key.

Chapter
Coordination Compounds
Topic
Crystal Field Theory
Idea tested
High and Low Spin States

Same idea in other shifts

Asked 19× in all
  1. 4 Apr 2026, Shift 2 · Q60Consider the metal complexes [Ni(en)3]2+\mathrm{[Ni(en)_3]^{2+}} (A), [NiCl4]2−\mathrm{[NiCl_4]^{2-}} (B) and [Ni(NH3)6]2+\mathrm{[Ni(NH_3)_6]^{2+}} (C). Choose the…MediumSingle correct
  2. 5 Apr 2026, Shift 2 · Q71The total number of unpaired electrons present in the d3d^3, d4d^4 (low spin) d5d^5 (high spin), d6d^6 (high spin) and d7d^7 (low spin)…EasyNumerical value
  3. 6 Apr 2026, Shift 2 · Q61Which of the following sequences of hybridisation, geometry and magnetic nature are correct for the given coordination compounds ? A.…MediumOther
  4. 8 Apr 2026, Shift 2 · Q71Number of paramagnetic complexes among the following is ________. [MnBr4]2−[\mathrm{MnBr_4}]^{2-}, [NiCl4]2−[\mathrm{NiCl_4}]^{2-},…MediumNumerical value
  5. 2 Apr 2025, Shift 1 · Q60Given below are two statements : Statement (I) : In octahedral complexes, when Δo<\Delta_o< P high spin complexes are formed. When…EasyTwo statements
  6. 2 Apr 2025, Shift 1 · Q74A transition metal (M) among Mn, Cr, Co and Fe has the highest standard electrode potential (M3+/M2+\mathrm{M^{3+}/M^{2+}}). It forms a metal…MediumNumerical value
  7. 2 Apr 2025, Shift 2 · Q61The type of hybridization and the magnetic property of [MnCl6]3−\mathrm{[MnCl_6]^{3-}} are,MediumSingle correct
  8. 3 Apr 2025, Shift 2 · Q62Identify the diamagnetic octahedral complex ions from below ; A. [Mn(CN)6]3−[\mathrm{Mn(CN)_6}]^{3-} B. [Co(NH3)6]3+[\mathrm{Co(NH_3)_6}]^{3+} C.…MediumOther

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.