JEE Main 2017 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 2 April 2017 (offline), Chemistry Q37

Question 37 of 90 in this shift, Chemistry question 7 of 30.

The 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 a dimer in benzene, percentage association of acetic acid in benzene will be : (

K_f

for benzene

=5.12\ \mathrm{K\,kg\,mol^{-1}}

)

(1)74.6%
(2)94.6%Official answer
(3)64.6%
(4)80.4%

Official answer

Option 2

CBSE answer key (25/04/2017, used for result).

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
26 Feb 2021, Shift 2 · Q55When 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…MediumNumerical value
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

Question text from the official JEE Main paper published by NTA (CBSE ran the 2017 exam); 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.