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Friday, 9 October

NEET UG 2017 · Chemistry · Question 81

NEET 2017 Chemistry, question 81

Question 81 of the NEET 2017 paper (code A) is a Chemistry question from Chemical Kinetics. Its idea, First Order Integrated Rate Law, was asked 4 times, in 2017, 2020, 2022 and 2025, across NEET 2017–2026. The CBSE official answer key gives option 2.

Updated 2026-10-08

Q81 · Chemistry

A first order reaction has a specific reaction rate of 10−210^{-2} sec−1\mathrm{sec^{-1}}. How much time will it take for 20 g of the reactant to reduce to 5 g ?

  1. 1238.6 sec
  2. 2138.6 secOfficial answer
  3. 3346.5 sec
  4. 4693.0 sec

Official answer: option 2 · CBSE official answer key

Same idea

First Order Integrated Rate Law, in other papers

NEET asked this idea 4 times, in 2017, 2020, 2022 and 2025. The other 3 questions below.

  • 2025 Q89If the rate constant of a reaction is 0.03 s−1^{-1}, how much time does it take for 7.2 mol L−1^{-1} concentration of the reactant to get…Numerical · Medium
  • 2022 Q92For a first order reaction A →\to Products, initial concentration of A is 0.1 M, which becomes 0.001 M after 5 minutes. Rate constant for…Numerical · Easy
  • 2020 Q132The rate constant for a first order reaction is 4.606×10−34.606\times10^{-3} s−1^{-1}. The time required to reduce 2.0 g of the reactant to 0.2 g…Numerical · Easy

First Order Integrated Rate Law: every question and how it was framed

The chapter

Chemical Kinetics in ten years of NEET

21 questions from 2017–2026, asked in 10 of 10 papers, about 2.0 a paper. Chemical Kinetics alone had 21.

Chapter analysisStudy this chapterPractise this chapter

Chemical Kinetics: questions per paper

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