JEE Main 2023 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 10 April 2023, Shift 1, Chemistry Q87

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

A molecule undergoes two independent first order reactions whose respective half lives are 12 min and 3 min. If both the reactions are occurring then the time taken for the 50% consumption of the reactant is ____________ min. (Nearest integer)

Official answer

NTA final key.

Chapter: Chemical Kinetics
Topic: Integrated Rate Equations
Idea tested: Parallel First-Order Effective Rate Constant

Same topic in other shifts

All Integrated Rate Equations questions

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4 Apr 2026, Shift 1 · Q57Consider the first order reaction $\mathrm{R}\rightarrow\mathrm{P}$ . The fraction of molecules decomposed in the given first order…EasySingle correct
4 Apr 2026, Shift 2 · Q63Consider the given graph showing variation of reactant concentration with time. Three different reactions were started with identical…MediumSingle correctHas a figure
4 Apr 2026, Shift 2 · Q74For a first order reaction $\mathrm{A\rightarrow B}$ [table: t/min = 0, x, 20; [A]/M = 0.6500, 0.0650, 0.00065] $x=$ ________ min.…MediumNumerical value
5 Apr 2026, Shift 1 · Q57First order gas phase reaction $\mathrm{A \rightarrow B + C}$ $p_i$ = initial pressure of gas A, $p_t$ = total pressure of the reaction…MediumSingle 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.