Learn

Saturday, 31 October

JEE Main 2024 · ChemistryNumerical answerNumerical valueHardMulti-step

JEE Main 5 April 2024, Shift 1, Chemistry Q87

Question 87 of 90 in this shift, Chemistry question 27 of 30, Section B.

In a borax bead test under hot condition, a metal salt (one from the given) is heated at point B of the flame, resulted in green colour salt bead. The spin-only magnetic moment value of the salt is ________ BM (Nearest integer) [Given atomic number of Cu = 29, Ni = 28, Mn = 25, Fe = 26]

The figure, in words

Sketch of a loop (platinum wire) with a bead, flame zones labelled A (upper) and B (lower).

Official answer

6

NTA final key.

Chapter
The d- and f-Block Elements
Topic
d-Block Elements
Idea tested
Spin-only Magnetism

Same idea in other shifts

Asked 23× in all
  1. 2 Apr 2026, Shift 2 · Q74Number of paramagnetic ions among the following d- and f-block metal ions is __________.…MediumNumerical value
  2. 4 Apr 2026, Shift 2 · Q62Consider ∣x∣|x| is the difference in oxidation states of Mn in highest manganese fluoride and highest manganese oxide. The ions with ∣x∣|x|…MediumOther
  3. 3 Apr 2025, Shift 1 · Q62The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are : A. Cr2+\mathrm{Cr^{2+}} B. Fe2+\mathrm{Fe^{2+}} C.…EasyOther
  4. 8 Apr 2025, Shift 2 · Q58The correct decreasing order of spin only magnetic moment values (BM) of Cu+\mathrm{Cu^+}, Cu2+\mathrm{Cu^{2+}}, Cr2+\mathrm{Cr^{2+}} and…EasySingle correct
  5. 4 Apr 2024, Shift 2 · Q69A first row transition metal in its +2 oxidation state has a spin-only magnetic moment value of 3.86 BM. The atomic number of the metal isEasySingle correct
  6. 5 Apr 2024, Shift 1 · Q86The spin-only magnetic moment value of the ion among Ti2+\mathrm{Ti^{2+}}, V2+\mathrm{V^{2+}}, Co3+\mathrm{Co^{3+}} and Cr2+\mathrm{Cr^{2+}},…MediumNumerical value
  7. 6 Apr 2024, Shift 1 · Q86Among CrO, Cr2O3\mathrm{Cr_2O_3} and CrO3\mathrm{CrO_3}, the sum of spin-only magnetic moment values of basic and amphoteric oxides is ________…MediumNumerical value
  8. 6 Apr 2024, Shift 1 · Q87The difference in the 'spin-only' magnetic moment values of KMnO4\mathrm{KMnO_4} and the manganese product formed during titration of…MediumNumerical value

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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.