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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 9 January 2020, Shift 1, Chemistry Q27

Question 27 of 75 in this shift, Chemistry question 2 of 25, Section A.

If the magnetic moment of a dioxygen species is 1.73 B.M, it may be :
  1. (1)O2\mathrm{O_2} or O2−\mathrm{O_2^-}
  2. (2)O2\mathrm{O_2} or O2+\mathrm{O_2^+}
  3. (3)O2−\mathrm{O_2^-} or O2+\mathrm{O_2^+}Official answer
  4. (4)O2\mathrm{O_2}, O2−\mathrm{O_2^-} or O2+\mathrm{O_2^+}

Official answer

Option 3

NTA final key (Jan 2020).

Chapter
Chemical Bonding and Molecular Structure
Topic
Molecular Orbital Theory
Idea tested
Magnetic Property Prediction

Same idea in other shifts

Asked 9× in all
  1. 4 Apr 2024, Shift 1 · Q82Number of molecules/species from the following having one unpaired electron is ________. O2\mathrm{O_2}, O2−1\mathrm{O_2^{-1}}, NO,…MediumNumerical value
  2. 9 Apr 2024, Shift 1 · Q82The total number of species from the following in which one unpaired electron is present, is ________.…MediumNumerical value
  3. 13 Apr 2023, Shift 1 · Q62In which of the following processes, the bond order increases and paramagnetic character changes to diamagnetic one ?MediumSingle correct
  4. 25 Jul 2022, Shift 1 · Q81Among the following species N2, N2+, N2−, N22−, O2, O2+, O2−, O22−\mathrm{N_2,\ N_2^{+},\ N_2^{-},\ N_2^{2-},\ O_2,\ O_2^{+},\ O_2^{-},\ O_2^{2-}} the number of species…MediumNumerical value
  5. 28 Jul 2022, Shift 1 · Q83The number of paramagnetic species among the following is __________.…MediumNumerical value
  6. 4 Aug 2021, Shift 1 · Q32Consider the following species B2,C2,S2,NO,O22−\mathrm{B_2, C_2, S_2, NO, O_2^{2-}} Which set represents all paramagnetic species?MediumSingle correct
  7. 31 Aug 2021, Shift 2 · Q54According to molecular orbital theory, the number of unpaired electron(s) in O22−\mathrm{O_2^{2-}} is __________.EasyNumerical value
  8. 2 Apr 2017 (offline) · Q42Which of the following species is **not** paramagnetic ?EasySingle 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.