Learn

Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumMulti-step

JEE Main 4 August 2021, Shift 2, Chemistry Q55

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

The standard reaction enthalpy for hydrogenation of propene is −124 kJ mol−1-124\ \mathrm{kJ\ mol^{-1}}. Additionally, standard heat of combustion ΔcH⊖\Delta_c H^{\ominus}(propane) = −2220 kJ mol−1-2220\ \mathrm{kJ\ mol^{-1}}. and standard heat of formation ΔfH⊖\Delta_f H^{\ominus}(water) = −286 kJ mol−1-286\ \mathrm{kJ\ mol^{-1}}. If ΔcH⊖\Delta_c H^{\ominus}(propene) = −x kJ mol−1-x\ \mathrm{kJ\ mol^{-1}}, the value of xx is ________ . (Nearest integer)

Official answer

2058

NTA final key.

Chapter
Thermodynamics (Chemistry)
Topic
Enthalpy and Hess's Law
Idea tested
Hess's Law

Same idea in other shifts

Asked 5× in all
  1. 2 Apr 2026, Shift 1 · Q54Consider the following data. (i) 2Al(s)+6HCl(aq)→Al2Cl6(aq)+3H2(g)+1200\mathrm{2Al(s)+6HCl(aq)\rightarrow Al_2Cl_6(aq)+3H_2(g)}+1200 kJ/mol (ii)…HardSingle correct
  2. 30 Jan 2024, Shift 2 · Q82Two reactions are given below:…EasyNumerical value
  3. 25 Jul 2022, Shift 1 · Q82The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are −2220.0 kJ mol−1-2220.0\ \mathrm{kJ\,mol^{-1}},…EasyNumerical value
  4. 2 Apr 2017 (offline) · Q31Given C(graphite)+O2(g)→CO2(g)\mathrm{C_{(graphite)}+O_2(g)\rightarrow CO_2(g)} ; ΔrH∘=−393.5 kJ mol−1\Delta_rH^\circ=-393.5\ \mathrm{kJ\,mol^{-1}}…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 108 of the 174 JEE Main shifts held from 2017 to 2026.