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Saturday, 31 October

JEE Main 2020 · ChemistryNumerical answerNumerical valueHardMulti-step

JEE Main 9 January 2020, Shift 2, Chemistry Q46

Question 46 of 75 in this shift, Chemistry question 21 of 25, Section B.

A cylinder containing an ideal gas (0.1 mol of 1.0 dm3^3) is in thermal equilibrium with a large volume of 0.5 molal aqueous solution of ethylene glycol at its freezing point. If the stoppers S1S_1 and S2S_2 (as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be ______. (Given, KfK_f (water) =2.0= 2.0 K kg mol−1^{-1}, R=0.08R = 0.08 dm3^3 atm K−1^{-1} mol−1^{-1})

The figure, in words

Cylinder holding ideal gas, with a frictionless piston on top held by stoppers S1 and S2, immersed in a large bath of aqueous ethylene glycol.

Official answer

2.17 to 2.23

NTA final key (Jan 2020). Any value in the range scored.

Chapter
Solutions
Topic
Colligative Properties
Idea tested
Freezing Point Depression

Same idea in other shifts

Asked 16× in all
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  2. 5 Apr 2024, Shift 2 · Q84Considering acetic acid dissociates in water, its dissociation constant is 6.25×10−56.25\times10^{-5}. If 5 mL of acetic acid is dissolved in 1…HardNumerical value
  3. 6 Apr 2024, Shift 2 · Q84When 'xx' ×10−2\times 10^{-2} mL methanol (molar mass =32= 32 g; density =0.792= 0.792 g/cm3^3) is added to 100 mL water (density =1= 1…MediumNumerical valueHas a figure
  4. 30 Jan 2024, Shift 1 · Q63What happens to freezing point of benzene when small quantity of napthalene is added to benzene ?EasySingle correct
  5. 25 Jul 2022, Shift 2 · Q62Two solutions A and B are prepared by dissolving 1 g of non-volatile solutes X and Y, respectively in 1 kg of water. The ratio of…EasySingle correct
  6. 28 Jul 2022, Shift 1 · Q84150 g of acetic acid was contaminated with 10.2 g ascorbic acid (C6H8O6\mathrm{C_6H_8O_6}) to lower down its freezing point by…EasyNumerical value
  7. 30 Jul 2022, Shift 2 · Q5331 g of ethylene glycol is mixed with 500 g of water. The freezing point of the aqueous solution is ________ K. (in nearest integer)…EasyNumerical value
  8. 3 Aug 2021, Shift 2 · Q32The lowest freezing point among the following solutions will be observed in [Atomic weight : C = 12, Mg = 24, Na = 23, Cl = 35.5, O = 16,…EasySingle 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.