The depression in freezing point observed for a formic acid solution of concentration $0.5\ \mathrm{mL\,L^{-1}}$ is $0.0405^\circ$C. Density of formic acid is $1.05\ \mathrm{g\,mL^{-1}}$. The Van't Hoff factor of the formic acid solution is nearly : (Given for water $k_f=1.86\ \mathrm{k\,kg\,mol^{-1}}$)

JEE Main 2022 · ChemistryMultiple choiceSingle correctMediumCalculation

JEE Main 25 July 2022, Shift 1, Chemistry Q63

Question 63 of 90 in this shift, Chemistry question 3 of 30, Section A.

The depression in freezing point observed for a formic acid solution of concentration

0.5\ \mathrm{mL\,L^{-1}}

0.0405^\circ

C. Density of formic acid is

1.05\ \mathrm{g\,mL^{-1}}

. The Van't Hoff factor of the formic acid solution is nearly : (Given for water

k_f=1.86\ \mathrm{k\,kg\,mol^{-1}}

)

(1) $0.8$
(2) $1.1$
(3) $1.9$ Official answer
(4) $2.4$

Official answer

Option 3

NTA final key (2022 Session 2).

Chapter: Solutions
Topic: Colligative Properties
Idea tested: Van't Hoff Factor (i)

Same idea in other shifts

Asked 7× in all

1 Feb 2024, Shift 1 · Q64We have three aqueous solutions of NaCl labelled as 'A', 'B' and 'C' with concentration 0.1 M, 0.01 M and 0.001 M, respectively. The value…MediumSingle correct
12 Apr 2023, Shift 1 · Q8480 mole percent of $\mathrm{MgCl_2}$ is dissociated in aqueous solution. The vapour pressure of 1.0 molal aqueous solution of…MediumNumerical value
4 Aug 2021, Shift 2 · Q560.7 $\mathrm{cm^3}$ of compound A (molar mass = 70 $\mathrm{g\ mol^{-1}}$ , density = 1.024 $\mathrm{g\ cm^{-3}}$ ) is dissolved in 1…MediumNumerical value
26 Aug 2021, Shift 1 · Q54Of the following four aqueous solutions, total number of those solutions whose freezing point is lower than that of 0.10 M…EasyNumerical value
31 Aug 2021, Shift 1 · Q33Which one of the following 0.10 M aqueous solutions will exhibit the largest freezing point depression ?EasySingle correct
25 Feb 2021, Shift 1 · Q541 molal aqueous solution of an electrolyte $\mathrm{A_2B_3}$ is 60% ionised. The boiling point of the solution at 1 atm is ________ K.…MediumNumerical value

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.