The correct order of the number of unpaired electrons in the given complexes is A. $[\mathrm{Fe(CN)_6}]^{3-}$ B. $[\mathrm{FeF_6}]^{3-}$ C. $[\mathrm{CoF_6}]^{3-}$ D. $[\mathrm{Cr(oxalate)_3}]^{3-}$ E. $[\mathrm{Ni(CO)_4}]$ Choose the correct answer from the options given below:

JEE Main 2023 · ChemistryMultiple choiceOtherMediumApplication

JEE Main 10 April 2023, Shift 2, Chemistry Q69

Question 69 of 90 in this shift, Chemistry question 9 of 30, Section A.

The correct order of the number of unpaired electrons in the given complexes is A.

[\mathrm{Fe(CN)_6}]^{3-}

[\mathrm{FeF_6}]^{3-}

[\mathrm{CoF_6}]^{3-}

[\mathrm{Cr(oxalate)_3}]^{3-}

[\mathrm{Ni(CO)_4}]

Choose the correct answer from the options given below:

(1)E < A < B < D < C
(2)A < E < D < C < B
(3)E < A < D < C < BOfficial answer
(4)A < E < C < B < D

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 34× in all

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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
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2 Apr 2025, Shift 1 · Q60Given below are two statements : Statement (I) : In octahedral complexes, when $\Delta_o<$ P high spin complexes are formed. When…EasyTwo statements
2 Apr 2025, Shift 1 · Q74A transition metal (M) among Mn, Cr, Co and Fe has the highest standard electrode potential ( $\mathrm{M^{3+}/M^{2+}}$ ). It forms a metal…MediumNumerical value
2 Apr 2025, Shift 2 · Q61The type of hybridization and the magnetic property of $\mathrm{[MnCl_6]^{3-}}$ are,MediumSingle correct
3 Apr 2025, Shift 2 · Q62Identify the diamagnetic octahedral complex ions from below ; A. $[\mathrm{Mn(CN)_6}]^{3-}$ B. $[\mathrm{Co(NH_3)_6}]^{3+}$ 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 108 of the 174 JEE Main shifts held from 2017 to 2026.