The Born-Haber cycle for KCl is evaluated with the following data: Δ _ f H ^ Θ forKCl = - 436.7 kJmol ^ - 1 ; Δ _ sub H ^ Θ forK = 89.2 kJmol ^ - 1 ; Δ _ ionization H ^ Θ forK = 419.0kJ mol ^ - 1 ; Δ _ electron gain H ^

Correct answer: 0 So, Δ _ f H ^ Θ = Δ _ f H ^ Θ (KCl) = Δ _ sub H ^ Θ + Δ _ 1st ionisation H ^ Θ (K) + 1 / 2 Δ _ bond H ^ Θ ( Cl _ 2 ( g ) ) + Δ _ electron gain H ^ Θ + Δ _ lattice H ^ Θ - 436 . 7 = 89 . 2 + 419 + (1)/(2)(243) + (- 348 . 6) + Δ _ lattice H ^ Θ Δ _ lattice H ^ Θ = - 717 . 8kJ mole ^ - 1 - 718kJ mole ^ - 1

JEE Main 202126 AugustMorning Shift

Exam: JEE Main
Year: 2021
Date: 26 August
Shift: Morning Shift
Subject: Chemistry
Chapter: Thermodynamics (C)

JEE Main 2021 · 26 August · Morning Shift · Chemistry · Thermodynamics (C)

The Born-Haber cycle for KCl is evaluated with the following data:...

The Born-Haber cycle for $KCl$ is evaluated with the following data:
${\Delta}_{f}{H}^{Θ}\text{for}KCl = - 436.7{kJmol}^{- 1}; {\Delta}_{sub}{H}^{Θ}\text{for}K = 89.2{kJmol}^{- 1};$

${\Delta}_{\text{ionization}}{H}^{Θ}\text{for}K = 419.0kJ{\text{mol}}^{- 1}; {\Delta}_{\text{electron gain}}{H}^{Θ}\text{for}{Cl}_{( g )} = - 348.6{kJmol}^{- 1}$

${\Delta}_{\text{bond}}{H}^{Θ}\text{for}{Cl}_{2} = 243.0{kJmol}^{- 1}$
The magnitude of lattice enthalpy of $KCl$ in ${kJmol}^{- 1}$ is (Nearest integer)

The Born-Haber cycle for KCl is evaluated with the following data: Δ _ f H ^ Θ forKCl = - 436.7 kJmol ^ - 1 ; Δ _ sub H

Correct answer

Step-by-step solution

The Born-Haber cycle for KCl is evaluated with the following data: Δ _ f H ^ Θ forKCl = - 436.7 kJmol ^ - 1 ; Δ _ sub H

So, ${\Delta}_{f}{H}^{Θ} = {\Delta}_{f}{H}^{Θ}\left(KCl\right) = {\Delta}_{\text{sub}}{H}^{Θ} + {\Delta}_{\text{1st ionisation}}{H}^{Θ}\left(K\right) + 1 / 2{\Delta}_{bond}{H}^{Θ}\left({Cl}_{2 ( g )}\right) + {\Delta}_{\text{electron gain}}{H}^{Θ} + {\Delta}_{\text{lattice}}{H}^{Θ} - 436 . 7 = 89 . 2 + 419 + \dfrac{1}{2}\left(243\right) + \left(- 348 . 6\right) + {\Delta}_{\text{lattice}}{H}^{Θ}$

${\Delta}_{\text{lattice}}{H}^{Θ} = - 717 . 8kJ{mole}^{- 1} \approx - 718kJ{mole}^{- 1}$

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