JEE Main · Chemistry · Some Basic Concepts of Chemistry
Molecular Formula Determination
JEE Main asked Molecular Formula Determination 2 times in 2 of the 108 shifts Lumi analysed, in 2023 and 2024. It belongs to Mole Concept, in Some Basic Concepts of Chemistry (Chemistry). The longest wait between two years asking it was 1 year.
Updated 2026-10-24
- Times asked
- 2
- in 2 shifts
- Years
- 2 of 8
- First asked
- 2023
- last in 2024
- Pattern
- Occasional
- across the analysed shifts
Questions on this idea a shift, by year
2017–2026. Asked in 2023 and 2024. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.
Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 0 in 24 shifts · 2022: 0 in 24 shifts · 2023: 1 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.
Shift by shift
Each square is one analysed shift, in date order. Open a filled one for that paper.
How JEE Main framed it
Single correct is the usual form. Skill tested: calculation.
- Molecular formula from percentage composition
- Metal chloride formula from percent and vapour mass
Difficulty
Every question was multiple choice.
Every question
All 2 questions
From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.
- 5 Apr 2024, Shift 1 · Q73An organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is :MediumSingle correct
- 12 Apr 2023, Shift 1 · Q61A metal chloride contains 55.0% of chlorine by weight . 100 mL vapours of the metal chloride at STP weigh 0.57 g. The molecular formula of…MediumSingle correct
Shifts: 12 Apr 2023, Shift 1, 5 Apr 2024, Shift 1.
Same topic
Other ideas in Mole Concept
Mole Concept has 18 ideas JEE Main has asked; 12 of them came up in more than one question. The 12 most asked are below.
- Molarity Calculation16× · 2024
- Mole and Avogadro Calculations11× · 2026
- PPM and Mass Percentage7× · 2025
- Empirical Formula from Mass Percentage6× · 2026
- Limiting Reagent and Reaction Yield6× · 2024
- Molar Mass and Gas Volume5× · 2026
- Mole Fraction Calculation5× · 2026
- Molarity and Molality Interconversion5× · 2024
- Normality and n-factor Calculation5× · 2023
- Molarity of Diluted and Mixed Solutions3× · 2025
- Molality Calculation3× · 2022
- Specific Gravity in Concentrationonce · 2024