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Saturday, 31 October

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JEE Main 26 August 2021, Shift 1, Chemistry Q53

Question 53 of 90 in this shift, Chemistry question 23 of 30, Section B.

The Born-Haber cycle for KCl is evaluated with the following data : ΔfH⊖\Delta_f \mathrm{H}^{\ominus} for KCl =−436.7= -436.7 kJ mol−1^{-1}; ΔsubH⊖\Delta_{sub} \mathrm{H}^{\ominus} for K =89.2= 89.2 kJ mol−1^{-1}; ΔionizationH⊖\Delta_{ionization} \mathrm{H}^{\ominus} for K =419.0= 419.0 kJ mol−1^{-1}; Δelectron gainH⊖\Delta_{electron\ gain} \mathrm{H}^{\ominus} for Cl(g)=−348.6\mathrm{Cl_{(g)}} = -348.6 kJ mol−1^{-1}; ΔbondH⊖\Delta_{bond} \mathrm{H}^{\ominus} for Cl2=243.0\mathrm{Cl_2} = 243.0 kJ mol−1^{-1} The magnitude of lattice enthalpy of KCl in kJ mol−1^{-1} is __________. (Nearest integer)

Official answer

718

NTA final key.

Chapter
Thermodynamics (Chemistry)
Topic
Enthalpy and Hess's Law
Idea tested
Born-Haber Cycle for Lattice Enthalpy

Same idea in other shifts

Asked 2× in all
  1. 25 Feb 2021, Shift 1 · Q57The ionization enthalpy of Na+\mathrm{Na^+} formation from Na(g)\mathrm{Na_{(g)}} is 495.8 kJ mol−1^{-1}, while the electron gain enthalpy of…EasyNumerical 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.