Consider the given data: (a) HCl ( g )+10 H 2 O ( I ) rightarrow HCl .10 H 2 O Δ H =-69.01 kJ mol -1 (b) HCl ( g )+40 H 2 O ( I ) rightarrow HCl .40 H 2 O Δ H =-72.79 kJ mol -1 Choose the correct statement:

The heat of dilution for the HCl ( HCl .10 H 2 O . to HCl .40 H 2 O ) is 3.78 kJ mol -1 .

Dissolution of gas in water is an endothermic process.

The heat of solution depends on the amount of solvent.

The heat of formation of HCl solution is represented by both (a) and (b).

Chemistry · Thermodynamics & Thermochemistry

JEE Main 2025 — 4 April, Evening Shift — Question 12

Consider the given data:

(a) $\mathrm{HCl}(\mathrm{g})+10 \mathrm{H}_{2} \mathrm{O}(\mathrm{I}) \rightarrow \mathrm{HCl} .10 \mathrm{H}_{2} \mathrm{O} \Delta \mathrm{H}=-69.01$ $\mathrm{kJ} \mathrm{mol}^{-1}$

(b) $\mathrm{HCl}(\mathrm{g})+40 \mathrm{H}_{2} \mathrm{O}(\mathrm{I}) \rightarrow \mathrm{HCl} .40 \mathrm{H}_{2} \mathrm{O} \Delta \mathrm{H}=-72.79$ $\mathrm{kJ} \mathrm{mol}^{-1}$

Choose the correct statement:

Option A:
Dissolution of gas in water is an endothermic process.
Option B:
The heat of solution depends on the amount of solvent.
Option C:
The heat of formation of HCl solution is represented by both (a) and (b).
Option D:
The heat of dilution for the $\mathrm{HCl}\left(\mathrm{HCl} .10 \mathrm{H}_{2} \mathrm{O}\right.$ to $\mathrm{HCl} .40 \mathrm{H}_{2} \mathrm{O}$ ) is $3.78 \mathrm{~kJ} \mathrm{~mol}^{-1}$ .
Correct

Answer: D

Step-by-step solution

$\mathrm{HCl}(\mathrm{g})+\infty \mathrm{H}_{2} \mathrm{O}(\mathrm{I}) \rightarrow \mathrm{HCl}(\mathrm{aq})$

Heat released the above process is heat of solution.

From reaction (b) - (a) we get heat of dilution for $\mathrm{HCl}\left(\mathrm{HCl} .10 \mathrm{H}_{2} \mathrm{O}\right.$ to $\left.\mathrm{HCl} .40 \mathrm{H}_{2} \mathrm{O}\right)$ as $3.78 \mathrm{~kJ} \mathrm{~mol}^{-1}$ .

Answer key and solution verified before publishing.

Practise Thermodynamics & Thermochemistry

Start with this question, then two more from the same chapter — with a tutor that explains every step. Free.

Solve a similar one free

Exam: JEE Main 2025
Paper: 4 April, Evening Shift
Subject: Chemistry
Chapter: Thermodynamics & Thermochemistry
Topic: Thermochemistry and Enthalpy Changes