JEE Main 2026 · ChemistryMultiple choiceSingle correctEasyCalculation

JEE Main 6 April 2026, Shift 1, Chemistry Q51

Question 51 of 75 in this shift, Chemistry question 1 of 25, Section A.

An oxide of iron contains 69.9% iron, its empirical formula, is: (Given : Molar mass of Fe and O are 56 and 16 g mol

^{-1}

respectively.)

(1) $\mathrm{FeO}$
(2) $\mathrm{Fe_2O_3}$ Official answer
(3) $\mathrm{Fe_3O_4}$
(4) $\mathrm{FeO_3}$

Official answer

Option 2

NTA final key.

Chapter: Some Basic Concepts of Chemistry
Topic: Mole Concept
Idea tested: Empirical Formula from Mass Percentage

Same idea in other shifts

Asked 6× in all

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2 Sep 2020, Shift 2 · Q50The ratio of the mass percentages of ‘C & H’ and ‘C & O’ of a saturated acyclic organic compound ‘X’ are 4 : 1 and 3 : 4 respectively.…HardNumerical 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.