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Friday, 9 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumData or graph

JEE Main 6 September 2020, Shift 2, Chemistry Q42

Question 42 of 75 in this shift, Chemistry question 17 of 25.

For a reaction, 4 M(s)+nO2(g)→2M2On(s)4\,\mathrm{M(s)}+n\mathrm{O_2(g)}\rightarrow 2\mathrm{M_2O_n(s)}, the free energy change is plotted as a function of temperature. The temperature below which the oxide is stable could be inferred from the plot as the point at which :
  1. (1)the slope changes from negative to positive
  2. (2)the slope changes from positive to negative
  3. (3)the free energy change shows a change from negative to positive valueOfficial answer
  4. (4)the slope changes from positive to zero

Official answer

Option 3

NTA final key (Sep 2020).

Chapter
General Principles and Processes of Isolation of Elements
Topic
Metallurgical Extraction
Idea tested
Ellingham Diagram Basics

Same topic in other shifts

All Metallurgical Extraction questions
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  3. 25 Jul 2022, Shift 1 · Q67The compound(s) that is(are) removed as slag during the extraction of copper is : (A) CaO\mathrm{CaO} (B) FeO\mathrm{FeO} (C)…MediumOther
  4. 28 Jul 2022, Shift 1 · Q66Which of the reaction is suitable for concentrating ore by leaching process ?EasySingle correct
  5. 29 Jun 2022, Shift 1 · Q67In isolation of which one of the following metals from their ores, the use of cyanide salt is not commonly involved ?MediumSingle correct
  6. 3 Aug 2021, Shift 2 · Q34Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Fluoride based compound…EasyAssertion–reason

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 42 of the 174 JEE Main shifts held from 2017 to 2026.