JEE Main 2021 · ChemistryNumerical answerNumerical valueEasyCalculation

JEE Main 18 March 2021, Shift 2, Chemistry Q57

Question 57 of 90 in this shift, Chemistry question 27 of 30, Section B.

A reaction has a half life of 1 min. The time required for 99.9% completion of the reaction is __________ min. (Round off to the Nearest Integer). [Use : ln 2 = 0.69; ln 10 = 2.3]

Official answer

NTA final key.

Chapter: Chemical Kinetics
Topic: Integrated Rate Equations
Idea tested: First Order Fractional Completion Shortcuts

Same idea in other shifts

Asked 6× in all

6 Apr 2024, Shift 1 · Q85Time required for 99.9% completion of a first order reaction is __________ times the time required for completion of 90% reaction.(nearest…EasyNumerical value
8 Apr 2024, Shift 1 · Q85Consider the following reaction $\mathrm{A + B \rightarrow C}$ The time taken for A to become $1/4^{\mathrm{th}}$ of its initial…MediumNumerical value
24 Jun 2022, Shift 2 · Q65For a first order reaction, the time required for completion of 90% reaction is 'x' times the half life of the reaction. The value of 'x'…EasySingle correct
28 Jun 2022, Shift 1 · Q88For a first order reaction A $\rightarrow$ B, the rate constant, k = $5.5 \times 10^{-14}$ $\mathrm{s^{-1}}$ . The time required for 67%…MediumNumerical value
24 Feb 2021, Shift 1 · Q58Gaseous cyclobutene isomerizes to butadiene in a first order process which has a ‘k’ value of $3.3\times10^{-4}\ \mathrm{s^{-1}}$ at 153°C.…MediumNumerical value

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.