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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumData or graph

JEE Main 9 January 2020, Shift 1, Chemistry Q33

Question 33 of 75 in this shift, Chemistry question 8 of 25, Section A.

According to the following diagram, A reduces BO2\mathrm{BO_2} when the temperature is :

The figure, in words

Graph of ΔG∘\Delta G^\circ/kJ mol−1^{-1} (vertical axis, ticks −600-600, −800-800, −1000-1000, −1200-1200 from top to bottom) against T(∘^\circC) (horizontal axis, ticks 0, 200, 400, 600, 800, 1000, 1200, 1400, 1600). Two lines: the upper one, labelled A+O2⟶AO2\mathrm{A + O_2 \longrightarrow AO_2}, is nearly straight and rises slowly across the whole range; the lower one, labelled B+O2⟶BO2\mathrm{B + O_2 \longrightarrow BO_2}, is flat from T = 0 to about 1200, then rises steeply, crosses the A line at about 1400 and ends above it at T = 1600.
  1. (1)<1400 ∘C< 1400\ ^\circ\mathrm{C}
  2. (2)>1400 ∘C> 1400\ ^\circ\mathrm{C}Official answer
  3. (3)>1200 ∘C> 1200\ ^\circ\mathrm{C} but <1400 ∘C< 1400\ ^\circ\mathrm{C}
  4. (4)<1200 ∘C< 1200\ ^\circ\mathrm{C}

Official answer

Option 2

NTA final key (Jan 2020).

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

Same idea in other shifts

Asked 2× in all
  1. 28 Jun 2022, Shift 1 · Q64Given are two statements one is labelled as Assertion A and other is labelled as Reason R. Assertion A :Magnesium can reduce…MediumAssertion–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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.