JEE Main 2022ChemistryChemical KineticsMediumNumerical

JEE Main 2022 — Chemical Kinetics Question with Solution

JEE Main 2022 (28 Jun Shift 2)

Question

A radioactive element has a half life of 200 days. The percentage of original activity remaining after 83 days is____(Nearest integer)
(Given : antilog 0.125=1.333, antilog 0.693=4.93)

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Show full solutionCorrect answer: 75
Correct answer
75

Step-by-step explanation

For first order reaction,

K=2.303tlogNoNt ... 1

Also, K=0.693t12 ... 2

Equating 1 and 2

Hence, 2.303tlogNoNt=0.693t12

2.30383logNoNt=0.693200

NoNt=43

%NtN0=0.75×100

=75%

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About this question

This is a previous-year question from JEE Main 2022, 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.