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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 26 August 2021, Shift 2, Chemistry Q39

Question 39 of 90 in this shift, Chemistry question 9 of 30, Section A.

Arrange the following Cobalt complexes in the order of increasing Crystal Field Stabilization Energy (CFSE) value. Complexes : [CoF6]3−[\mathrm{CoF_6}]^{3-}, [Co(H2O)6]2+[\mathrm{Co(H_2O)_6}]^{2+}, [Co(NH3)6]3+[\mathrm{Co(NH_3)_6}]^{3+} and [Co(en)3]3+[\mathrm{Co(en)_3}]^{3+} (the letters A, B, C and D are printed beneath the four complexes in this order) Choose the correct option :
  1. (1)A < B < C < D
  2. (2)B < C < D < A
  3. (3)C < D < B < A
  4. (4)B < A < C < DOfficial answer

Official answer

Option 4

NTA final key.

Chapter
Coordination Compounds
Topic
Crystal Field Theory
Idea tested
CFSE Calculation

Same idea in other shifts

Asked 11× in all
  1. 6 Apr 2026, Shift 1 · Q61Match the LIST-I with LIST-II List-I (Electronic configuration of tetrahedral metal ion) | List-II (Crystal Field Stabilization Energy…MediumMatch the list
  2. 2 Apr 2025, Shift 2 · Q60The d-orbital electronic configuration of the complex among [Co(en)3]3+\mathrm{[Co(en)_3]^{3+}}, [CoF6]3−\mathrm{[CoF_6]^{3-}},…MediumSingle correct
  3. 10 Apr 2023, Shift 2 · Q70Match List I with List II LIST I (Complex) A. [Ti(H2O)6]2+[\mathrm{Ti(H_2O)_6}]^{2+} B. [V(H2O)6]2+[\mathrm{V(H_2O)_6}]^{2+} C. [Mn(H2O)6]3+[\mathrm{Mn(H_2O)_6}]^{3+}…MediumMatch the list
  4. 12 Apr 2023, Shift 1 · Q72Match List I with List II LIST I (Complex) / LIST II (CFSE (Δo\Delta_o)) A. [Cu(NH3)6]2+\mathrm{[Cu(NH_3)_6]^{2+}} - I. −0.6-0.6 B.…MediumMatch the list
  5. 29 Jul 2022, Shift 1 · Q90[Fe(CN)6]3−\mathrm{[Fe(CN)_6]^{3-}} should be an inner orbital complex. Ignoring the pairing energy, the value of crystal field stabilization…MediumNumerical value
  6. 27 Jun 2022, Shift 1 · Q71Which of the following will have maximum stabilization due to crystal field ?MediumSingle correct
  7. 2 Sep 2020, Shift 1 · Q37Consider that a d6d^{6} metal ion (M2+\mathrm{M^{2+}}) forms a complex with aqua ligands, and the spin only magnetic moment of the complex…HardSingle correct
  8. 3 Sep 2020, Shift 1 · Q37The electronic spectrum of [Ti(H2O)6]3+\mathrm{[Ti(H_2O)_6]^{3+}} shows a single broad peak with a maximum at 20,300 cm−1\mathrm{cm^{-1}}. The crystal…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 108 of the 174 JEE Main shifts held from 2017 to 2026.