Identify the diamagnetic octahedral complex ions from below ; A. $[\mathrm{Mn(CN)_6}]^{3-}$ B. $[\mathrm{Co(NH_3)_6}]^{3+}$ C. $[\mathrm{Fe(CN)_6}]^{4-}$ D. $[\mathrm{Co(H_2O)_3F_3}]$ Choose the correct answer from the options given below:

JEE Main 2025 · ChemistryMultiple choiceOtherMediumApplication

JEE Main 3 April 2025, Shift 2, Chemistry Q62

Question 62 of 75 in this shift, Chemistry question 12 of 25, Section A.

Identify the diamagnetic octahedral complex ions from below ; A.

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

[\mathrm{Co(NH_3)_6}]^{3+}

[\mathrm{Fe(CN)_6}]^{4-}

[\mathrm{Co(H_2O)_3F_3}]

Choose the correct answer from the options given below:

(1)B and C OnlyOfficial answer
(2)B and D Only
(3)A and D Only
(4)A and C Only

Official answer

Option 1

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

4 Apr 2026, Shift 2 · Q60Consider the metal complexes $\mathrm{[Ni(en)_3]^{2+}}$ (A), $\mathrm{[NiCl_4]^{2-}}$ (B) and $\mathrm{[Ni(NH_3)_6]^{2+}}$ (C). Choose the…MediumSingle correct
5 Apr 2026, Shift 2 · Q71The total number of unpaired electrons present in the $d^3$ , $d^4$ (low spin) $d^5$ (high spin), $d^6$ (high spin) and $d^7$ (low spin)…EasyNumerical value
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
8 Apr 2026, Shift 2 · Q71Number of paramagnetic complexes among the following is ________. $[\mathrm{MnBr_4}]^{2-}$ , $[\mathrm{NiCl_4}]^{2-}$ ,…MediumNumerical value
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
4 Apr 2025, Shift 2 · Q60The correct order of $\mathrm{[FeF_6]^{3-}}$ , $\mathrm{[CoF_6]^{3-}}$ , $\mathrm{[Ni(CO)_4]}$ and $\mathrm{[Ni(CN)_4]^{2-}}$ complex…MediumSingle correct

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.