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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedEasyData or graph

JEE Main 4 September 2020, Shift 1, Chemistry Q28

Question 28 of 75 in this shift, Chemistry question 3 of 25.

For the equilibrium A⇌B\mathrm{A \rightleftharpoons B}, the variation of the rate of the forward (a) and reverse (b) reaction with time is given by :

The figure, in words

Four graphs of Rate of reaction (y-axis) against Time (x-axis), each with curves labelled a and b and a double-headed arrow labelled equilibrium. Stem prints 'A' followed by a stray tick before the equilibrium arrow.
  1. (1)[figure: graph of Rate of reaction vs Time; curve a falls from a high value, curve b rises from zero, the two curves meet and merge into a single level line at the point marked equilibrium]Official answer
  2. (2)[figure: graph of Rate of reaction vs Time; curve a falls from a high value, curve b rises from zero, they cross, then a levels off below b and b levels off above a, marked equilibrium]
  3. (3)[figure: graph of Rate of reaction vs Time; curve a falls and curve b rises, both level off with a staying above b at the end, marked equilibrium (the two remain separated by a gap)]
  4. (4)[figure: graph of Rate of reaction vs Time; curve a falls then turns up again, curve b rises then turns down again, so the two curves move apart after the closest point, marked equilibrium]

Official answer

Option 1

NTA final key (Sep 2020).

Chapter
Equilibrium
Topic
Chemical Equilibrium
Idea tested
Rate-Time Graph Analysis

Same topic in other shifts

All Chemical Equilibrium questions
  1. 4 Apr 2026, Shift 1 · Q55At T(K), the equilibrium constant of A2(g)+B2(g)⇌C(g)\mathrm{A_2}(g)+\mathrm{B_2}(g)\rightleftharpoons \mathrm{C}(g) is 2.7×10−52.7\times10^{-5}. What is the…EasySingle correct
  2. 5 Apr 2026, Shift 1 · Q74The values of pressure equilibrium constant recorded at different temperatures for the following equilibrium reaction have been given…MediumNumerical value
  3. 5 Apr 2026, Shift 2 · Q56The reaction A(g)⇌B(g)+C(g)\mathrm{A(g)\rightleftharpoons B(g)+C(g)} was initiated with the amount 'a' of A(g). At equilibrium it is found that the…MediumSingle correct
  4. 6 Apr 2026, Shift 1 · Q57One mole each of He and A(g) are taken in a 10 L closed flask and heated to 400 K to establish the following equilibrium.…MediumSingle correct
  5. 6 Apr 2026, Shift 2 · Q74In a closed flask at 600 K, one mole of X2Y4(g)\mathrm{X_2Y_4(g)} attains equilibrium as given below :…MediumNumerical value
  6. 8 Apr 2026, Shift 2 · Q55Consider the following reactions in which all the reactants and products are present in gaseous state 2 xy⇌x2+y22\,xy \rightleftharpoons x_2 + y_2…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. 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.