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Saturday, 31 October

JEE Main 2024 · ChemistryNumerical answerNumerical valueMediumMulti-step

JEE Main 8 April 2024, Shift 1, Chemistry Q85

Question 85 of 90 in this shift, Chemistry question 25 of 30, Section B.

Consider the following reaction A+B→C\mathrm{A + B \rightarrow C} The time taken for A to become 1/4th1/4^{\mathrm{th}} of its initial concentration is twice the time taken to become 1/2 of the same. Also, when the change of concentration of B is plotted against time, the resulting graph gives a straight line with a negative slope and a positive intercept on the concentration axis. The overall order of the reaction is ____________.

Official answer

1

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
  1. 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
  2. 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
  3. 28 Jun 2022, Shift 1 · Q88For a first order reaction A →\rightarrow B, the rate constant, k = 5.5×10−145.5 \times 10^{-14} s−1\mathrm{s^{-1}}. The time required for 67%…MediumNumerical value
  4. 24 Feb 2021, Shift 1 · Q58Gaseous cyclobutene isomerizes to butadiene in a first order process which has a ‘k’ value of 3.3×10−4 s−13.3\times10^{-4}\ \mathrm{s^{-1}}at 153°C.…MediumNumerical value
  5. 18 Mar 2021, Shift 2 · Q57A 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…EasyNumerical 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.