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Friday, 9 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctEasyApplication

JEE Main 6 September 2020, Shift 2, Chemistry Q43

Question 43 of 75 in this shift, Chemistry question 18 of 25.

A set of solutions is prepared using 180 g of water as a solvent and 10 g of different non-volatile solutes A, B and C. The relative lowering of vapour pressure in the presence of these solutes are in the order [Given, molar mass of A = 100 g mol−1^{-1}; B = 200 g mol−1^{-1}; C = 10,000 g mol−1^{-1}]
  1. (1)A>B>CA>B>COfficial answer
  2. (2)B>C>AB>C>A
  3. (3)C>B>AC>B>A
  4. (4)A>C>BA>C>B

Official answer

Option 1

NTA final key (Sep 2020).

Chapter
Solutions
Topic
Colligative Properties
Idea tested
Relative Lowering of VP

Same idea in other shifts

Asked 7× in all
  1. 6 Apr 2026, Shift 1 · Q56When 0.25 moles of a non-volatile, non-ionizable solute was dissolved in 1 mole of a solvent the vapor pressure of solution was xx % of…EasySingle correct
  2. 2 Apr 2025, Shift 1 · Q55A solution is made by mixing one mole of volatile liquid A with 3 moles of volatile liquid B. The vapour pressure of pure A is 200 mm Hg…MediumSingle correct
  3. 7 Apr 2025, Shift 2 · Q55Liquid A and B form an ideal solution. The vapour pressures of pure liquids A and B are 350 and 750 mm Hg respectively at the same…MediumSingle correct
  4. 9 Apr 2024, Shift 2 · Q84The vapor pressure of pure benzene and methyl benzene at 27∘27^\circC is given as 80 Torr and 24 Torr, respectively. The mole fraction of…MediumNumerical value
  5. 6 Apr 2023, Shift 1 · Q85Mass of Urea (NH2CONH2\mathrm{NH_2CONH_2}) required to be dissolved in 1000 g of water in order to reduce the vapour pressure of water by 25% is…MediumNumerical value
  6. 2 Sep 2020, Shift 1 · Q26An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of…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 42 of the 174 JEE Main shifts held from 2017 to 2026.