Learn

Friday, 9 October

JEE Main 2024 · ChemistryNumerical answerNumerical valueMediumMulti-step

JEE Main 6 April 2024, Shift 2, Chemistry Q84

Question 84 of 90 in this shift, Chemistry question 24 of 30, Section B.

When '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 g/cm3^3), the following diagram is obtained. x=x = ________ (nearest integer). [Given : Molal freezing point depression constant of water at 273.15 K is 1.86 K kg mol−1^{-1}]

The figure, in words

Vapour pressure vs temperature/K graph: curves for water, methanolic solution and frozen system; freezing points marked at 270.65 K (solution) and 273.15 K (water).

Official answer

543

NTA final key.

Chapter
Solutions
Topic
Colligative Properties
Idea tested
Freezing Point Depression

Same idea in other shifts

Asked 5× in all
  1. 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
  2. 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
  3. 18 Mar 2021, Shift 1 · Q542 molal solution of a weak acid HA has a freezing point of 3.885°C. The degree of dissociation of this acid is __________ ×10−3\times10^{-3}.…MediumNumerical value
  4. 9 Jan 2020, Shift 2 · Q46A 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…HardNumerical valueHas a figure

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