JEE Main 2021ChemistryChemical KineticsMediumNumerical

JEE Main 2021 — Chemical Kinetics Question with Solution

JEE Main 2021 (16 Mar Shift 1)

Question

The decomposition of formic acid on gold surface follows first order kinetics. If the rate constant at 300 K is 1.0×10-3 s-1 and the activation energy Ea=11.488 kJ mol-1, the rate constant at 200 K is _________ ×10-5 s-1. (Round of to the Nearest Integer).

(Given R=8.314 J mol-1 K-1)

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Show full solutionCorrect answer: 10
Correct answer
10

Step-by-step explanation

K300=10-3   K200=?

Ea=11.488KJ/mole  R=8.314 J/mole-K

so ℓnK300 K200=EaR1200-1300

ℓnK300 K200=11.488×1000×1008.314×200×300

=2.303

=ℓn10

so K300 K200=10

K200=110×K300=10-4

=10×10-5 sec-1

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About this question

This is a previous-year question from JEE Main 2021, 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.