JEE Main 2024ChemistryChemical KineticsEasyNumerical

JEE Main 2024 — Chemical Kinetics Question with Solution

JEE Main 2024 (31 Jan Shift 2)

Question

r=kA for a reaction, 50% of A is decomposed in 120 minutes. The time taken for 90% decomposition of A is ______ minutes.

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Show full solutionCorrect answer: 399
Correct answer
399

Step-by-step explanation

r=kA

So, order of reaction =1

t1/2=120 min

k=0.693t1/2

For 90% completion of reaction,

⇒k=2.303tlogaa−xa=100,(a-x)=10

By putting the values in above equation,

⇒0.693t1/2=2.303tlog10010

∴ t=399 min

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About this question

This is a previous-year question from JEE Main 2024, covering the Chemical Kinetics chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.