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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctEasyRecall

JEE Main 2 September 2020, Shift 1, Chemistry Q38

Question 38 of 75 in this shift, Chemistry question 13 of 25.

The statement that is not true about ozone is :
  1. (1)in the stratosphere, it forms a protective shield against UV radiation.
  2. (2)in the atmosphere, it is depleted by CFCs.
  3. (3)it is a toxic gas and its reaction with NO gives NO2\mathrm{NO_2}.
  4. (4)in the stratosphere, CFCs release chlorine free radicals (Cl⋅\mathrm{Cl^{\cdot}}) which reacts with O3\mathrm{O_3} to give chlorine dioxide radicals.Official answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter
Environmental Chemistry
Topic
Environmental Chemistry
Idea tested
Ozone Layer Depletion

Same idea in other shifts

Asked 8× in all
  1. 8 Apr 2023, Shift 2 · Q70Which of these reactions is not a part of breakdown of ozone in stratosphere?MediumSingle correct
  2. 11 Apr 2023, Shift 2 · Q71Which of the following compounds is an example of Freon?EasySingle correct
  3. 13 Apr 2023, Shift 1 · Q72The radical which mainly causes ozone depletion in the presence of UV radiations is :EasySingle correct
  4. 26 Jul 2022, Shift 1 · Q70C˙l+CH4→A+B\dot{\mathrm{C}}\mathrm{l} + \mathrm{CH_4} \rightarrow \mathrm{A} + \mathrm{B} A and B in the above atmospheric reaction step are :EasySingle correct
  5. 4 Aug 2021, Shift 1 · Q41In stratosphere, chlorofluorocarbon compounds break down by UV radiations, releasing 'X' free radical, which further causes ozone layer…EasySingle correct
  6. 27 Aug 2021, Shift 1 · Q41The gas ‘A’ is having very low reactivity reaches to stratosphere. It is non-toxic and non-flammable but dissociated by UV-radiations in…EasySingle correctHas a figure
  7. 25 Jul 2021, Shift 2 · Q41Given below are two statements : Statement I : Chlorofluoro carbons breakdown by radiation in the visible energy region and release…MediumTwo statements

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.