JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 26 February 2021, Shift 2, Chemistry Q55

Question 55 of 90 in this shift, Chemistry question 25 of 30, Section B.

When 12.2 g of benzoic acid is dissolved in 100 g of water, the freezing point of solution was found to be

-0.93^\circ

C (

\mathrm{K_f}

(

\mathrm{H_2O}

)

= 1.86

K kg

\mathrm{mol^{-1}}

). The number (n) of benzoic acid molecules associated (assuming 100% association) is __________.

Official answer

NTA final key.

Chapter: Solutions
Topic: Colligative Properties
Idea tested: Degree of Association from Van't Hoff Factor

Same idea in other shifts

Asked 4× in all

25 Jun 2022, Shift 2 · Q63Solute A associates in water. When 0.7 g of solute A is dissolved in 42.0 g of water, it depresses the freezing point by 0.2 °C. The…MediumSingle correct
18 Mar 2021, Shift 2 · Q54A solute A dimerizes in water. The boiling point of a 2 molal solution of A is 100.52℃. The percentage association of A is __________.…MediumNumerical value
2 Apr 2017 (offline) · Q37The freezing point of benzene decreases by 0.45°C when 0.2 g of acetic acid is added to 20 g of benzene. If acetic acid associates to form…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 108 of the 174 JEE Main shifts held from 2017 to 2026.