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Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 27 August 2021, Shift 2, Chemistry Q59

Question 59 of 90 in this shift, Chemistry question 29 of 30, Section B.

The first order rate constant for the decomposition of CaCO3\mathrm{CaCO_3} at 700 K is 6.36×10−36.36 \times 10^{-3} s−1\mathrm{s^{-1}} and activation energy is 209 kJ mol−1\mathrm{mol^{-1}}. Its rate constant (in s−1\mathrm{s^{-1}}) at 600 K is x×10−6x \times 10^{-6}. The value of xx is __________. (Nearest integer) [Given R = 8.31 J K−1\mathrm{K^{-1}} mol−1\mathrm{mol^{-1}} ; log 6.36×10−36.36 \times 10^{-3} = −2.19-2.19, 10−4.79=1.62×10−510^{-4.79} = 1.62 \times 10^{-5}]

Official answer

16

NTA final key.

Chapter
Chemical Kinetics
Topic
Arrhenius Equation
Idea tested
Two-Point Arrhenius Equation

Same idea in other shifts

Asked 7× in all
  1. 2 Apr 2026, Shift 1 · Q74For reaction A→P\mathrm{A\rightarrow P}, rate constant k=1.5×103 s−1k=1.5\times10^3\ \mathrm{s^{-1}} at 27∘27^\circC If activation energy for the above…MediumNumerical value
  2. 8 Apr 2026, Shift 2 · Q57Given below are two statements : R=8.314 J K−1 mol−1R = 8.314\ \mathrm{J\,K^{-1}\,mol^{-1}} and 1 cal = 4.2 J Statement I : When Ea = 12.6 kcal/mol, the…MediumTwo statementsHas a figure
  3. 29 Jun 2022, Shift 1 · Q85The activation energy of one of the reactions in a biochemical process is 532611 J mol−1532611\ \mathrm{J\ mol^{-1}}. When the temperature falls from…MediumNumerical value
  4. 25 Feb 2021, Shift 2 · Q57The rate constant of a reaction increases by five times on increase in temperature from 27∘^\circC to 52∘^\circC. The value of…MediumNumerical value
  5. 9 Jan 2020, Shift 2 · Q48A sample of milk splits after 60 min. at 300 K and after 40 min. at 400 K when the population of lactobacillus acidophilus in it doubles.…MediumNumerical value
  6. 6 Sep 2020, Shift 2 · Q48The rate of a reaction decreased by 3.555 times when the temperature was changed from 40 °C to 30 °C. The activation energy (in kJ…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.