Learn

Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumCalculation

JEE Main 9 January 2020, Shift 1, Chemistry Q29

Question 29 of 75 in this shift, Chemistry question 4 of 25, Section A.

For following reactions A→700 KProduct\mathrm{A \xrightarrow{700\ K} Product} A→catalyst500 KProduct\mathrm{A \xrightarrow[catalyst]{500\ K} Product} it was found that the Ea\mathrm{E_a} is decreased by 30 kJ/mol in the presence of catalyst. If the rate remains unchanged, the activation energy for catalysed reaction is (Assume pre exponential factor is same) :
  1. (1)105 kJ/mol
  2. (2)135 kJ/mol
  3. (3)75 kJ/molOfficial answer
  4. (4)198 kJ/mol

Official answer

Option 3

NTA final key (Jan 2020).

Chapter
Chemical Kinetics
Topic
Arrhenius Equation
Idea tested
Catalyst Effect on Arrhenius Parameters

Same idea in other shifts

Asked 4× in all
  1. 15 Apr 2023, Shift 1 · Q85For a reversible reaction A⇌B\mathrm{A \rightleftharpoons B}, the ΔHforward reaction=20\Delta H_{\text{forward reaction}} = 20 kJ mol−1\mathrm{mol^{-1}}. The…HardNumerical value
  2. 26 Jun 2022, Shift 2 · Q88Catalyst A reduces the activation energy for a reaction by 10 kJ mol−1\mathrm{mol^{-1}} at 300 K. The ratio of rate constants,…MediumNumerical value
  3. 8 Jan 2020, Shift 1 · Q27The rate of a certain biochemical reaction at physiological temperature (T) occurs 10610^6 times faster with enzyme than without. The…MediumSingle correct

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.