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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumRecall

JEE Main 31 August 2021, Shift 2, Chemistry Q34

Question 34 of 90 in this shift, Chemistry question 4 of 30, Section A.

Which one of the following statements is incorrect ?
  1. (1)Bond dissociation enthalpy of H2\mathrm{H_2} is highest among diatomic gaseous molecules which contain a single bond.
  2. (2)At around 2000 K, the dissociation of dihydrogen into its atoms is nearly 8.1%.Official answer
  3. (3)Dihydrogen is produced on reacting zinc with HCl as well as NaOH(aq)\mathrm{NaOH_{(aq)}}.
  4. (4)Atomic hydrogen is produced when H2\mathrm{H_2} molecules at a high temperature are irradiated with UV radiation.

Official answer

Option 2

NTA final key.

Chapter
Hydrogen
Topic
Hydrogen and Hydrides
Idea tested
H-H Bond Dissociation Enthalpy

Same idea in other shifts

Asked 3× in all
  1. 4 Aug 2021, Shift 1 · Q37Naturally occurring hydrogen contains three isotopes, protium (H), deuterium (D) and tritium (T). What is correct order of heat of…EasySingle correct
  2. 25 Jul 2021, Shift 1 · Q35At 298.2 K the relationship between enthalpy of bond dissociation (in kJ mol−1^{-1}) for hydrogen (EH\mathrm{E_H}) and its isotope,…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.