JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 18 March 2021, Shift 2, Chemistry Q39

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

The oxide that shows magnetic property is :

(1) $\mathrm{SiO_2}$
(2) $\mathrm{Mn_3O_4}$ Official answer
(3)MgO
(4) $\mathrm{Na_2O}$

Official answer

Option 2

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

2 Apr 2026, Shift 2 · Q74Number of paramagnetic ions among the following d- and f-block metal ions is __________.…MediumNumerical value
4 Apr 2026, Shift 2 · Q62Consider $|x|$ is the difference in oxidation states of Mn in highest manganese fluoride and highest manganese oxide. The ions with $|x|$ …MediumOther
3 Apr 2025, Shift 1 · Q62The metal ions that have the calculated spin-only magnetic moment value of 4.9 B.M. are : A. $\mathrm{Cr^{2+}}$ B. $\mathrm{Fe^{2+}}$ C.…EasyOther
8 Apr 2025, Shift 2 · Q58The correct decreasing order of spin only magnetic moment values (BM) of $\mathrm{Cu^+}$ , $\mathrm{Cu^{2+}}$ , $\mathrm{Cr^{2+}}$ and…EasySingle correct
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
5 Apr 2024, Shift 1 · Q86The spin-only magnetic moment value of the ion among $\mathrm{Ti^{2+}}$ , $\mathrm{V^{2+}}$ , $\mathrm{Co^{3+}}$ and $\mathrm{Cr^{2+}}$ ,…MediumNumerical value
5 Apr 2024, Shift 1 · Q87In 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…HardNumerical valueHas a figure
6 Apr 2024, Shift 1 · Q86Among CrO, $\mathrm{Cr_2O_3}$ and $\mathrm{CrO_3}$ , the sum of spin-only magnetic moment values of basic and amphoteric oxides is ________…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. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.