The hydration energies of K + and Cl - are -x and - y kJ / mol respectively. If lattice energy of KCl is -z kJ / mol , then the heat of solution of KCl is:

Chemistry · Thermodynamics & Thermochemistry

JEE Main 2025 — 7 April, Evening Shift — Question 16

The hydration energies of $\mathrm{K}^{+}$ and $\mathrm{Cl}^{-}$ are $-x$ and $-\mathrm{y} \mathrm{kJ} / \mathrm{mol}$ respectively. If lattice energy of KCl is $-z \mathrm{~kJ} / \mathrm{mol}$ , then the heat of solution of KCl is:

Option A:
$x+y+z$
Option B:
$-z-(x+y)$
Option C:
$+x-y-z$
Option D:
$z-(x+y)$
Correct

Answer: D

Step-by-step solution

$\Delta \mathrm{H}_{\text {solution }}=\left(-\Delta \mathrm{H}_{\text {L.E. }}\right)+\Delta \mathrm{H}_{\text {hydration }}$

$=-(-z)+(-x-y)$

$=z-(x+y)$

Answer key and solution verified before publishing.

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Exam: JEE Main 2025
Paper: 7 April, Evening Shift
Subject: Chemistry
Chapter: Thermodynamics & Thermochemistry
Topic: Thermochemistry and Enthalpy Changes

The correct statement amongst the following is

Answer: D

Step-by-step solution

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