Learn

Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 7 April 2025, Shift 2, Chemistry Q55

Question 55 of 75 in this shift, Chemistry question 5 of 25, Section A.

Liquid 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 temperature. If xAx_A and xBx_B are the mole fraction of A and B in solution while yAy_A and yBy_B are the mole fraction of A and B in vapour phase then,
  1. (1)xAxB>yAyB\frac{x_A}{x_B}>\frac{y_A}{y_B}Official answer
  2. (2)xAxB=yAyB\frac{x_A}{x_B}=\frac{y_A}{y_B}
  3. (3)(xA−yA)<(xB−yB)(x_A-y_A)<(x_B-y_B)
  4. (4)xAxB<yAyB\frac{x_A}{x_B}<\frac{y_A}{y_B}

Official answer

Option 1

NTA final key.

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. 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
  4. 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
  5. 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
  6. 6 Sep 2020, Shift 2 · Q43A 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…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. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.