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Friday, 9 October

JEE Main Chemistry · Thermodynamics (Chemistry)

Bond Enthalpy Calculations

Bond Enthalpy Calculations (Thermodynamics (Chemistry)) was asked 2 times in 2 JEE Main shifts, 2021–2025, out of the 42 shifts Lumi analysed. 2 of the 2 had a numerical answer.

Times asked
2
in 2 shifts
Years
2021–2025
Usual format
Numerical value
Calculation
Pattern
Occasional
repeats across shifts

How it is asked

  • Enthalpy of formation from bond enthalpies
  • Reaction enthalpy from bond enthalpies

Difficulty

Easy 1Medium 1Hard 0

Where it sits

Chapter: Thermodynamics (Chemistry). Topic: Enthalpy and Hess's Law, 24 questions over 14 ideas.

Other repeat ideas in this topic

Every time it came

All 2 questions

Newest first, each with its options and official answer.

  1. 3 Apr 2025, Shift 1 · Q71Given : ΔHsub⊖\Delta H^{\ominus}_{sub} [C (graphite)] = 710 kJ mol−1^{-1} ΔC−HH⊖\Delta_{C-H}H^{\ominus} = 414 kJ mol−1^{-1}…MediumNumerical value
  2. 18 Mar 2021, Shift 1 · Q53For the reaction C2H6→C2H4+H2\mathrm{C_2H_6 \rightarrow C_2H_4 + H_2} the reaction enthalpy ΔrH=\Delta_rH = __________ kJ mol−1^{-1}. (Round off to…EasyNumerical value