1
JEE Main 2025 (Online) 7th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

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

A

$x + y + z$

B

$z - (x + y)$

C

$-z - (x + y)$

D

$x - y - z$

2
JEE Main 2025 (Online) 7th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The correct statement amongst the following is :

A

The standard state of a pure gas is the pure gas at a pressure of 1 bar and temperature 273 K.

B

$\Delta_f H^{\circ}_{500}$ is zero for $O_2(g)$.

C

$\Delta_f H^{\circ}_{298}$ is zero for $O(g)$.

D

The term 'standard state' implies that the temperature is 0°C.

3
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Total enthalpy change for freezing of 1 mol of water at $10^{\circ} \mathrm{C}$ to ice at $-10^{\circ} \mathrm{C}$ is ________

(Given: $\Delta_{\text {fus }} \mathrm{H}=x \mathrm{~kJ} / \mathrm{mol}$

$$\begin{aligned} & \mathrm{C}_{\mathrm{p}}\left[\mathrm{H}_2 \mathrm{O}(\mathrm{l})\right]=y \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \\ & \mathrm{C}_{\mathrm{p}}\left[\mathrm{H}_2 \mathrm{O}(\mathrm{~s})\right]=z \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \end{aligned}$$

A
$-x-10 y-10 z$
B
$x-10 y-10 z$
C
$-10(100 x+y+z)$
D
$10(100 \mathrm{x}+y+z)$
4
JEE Main 2025 (Online) 4th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Consider the given data :

(a) $\mathrm{HCl}(\mathrm{g})+10 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{HCl} .10 \mathrm{H}_2 \mathrm{O} \Delta \mathrm{H}=-69.01 \mathrm{~kJ} \mathrm{~mol}^{-1}$

(b) $\mathrm{HCl}(\mathrm{g})+40 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{HCl} .40 \mathrm{H}_2 \mathrm{O} \Delta \mathrm{H}=-72.79 \mathrm{~kJ} \mathrm{~mol}^{-1}$

Choose the correct statement :

A
The heat of dilution for the $\mathrm{HCl}\left(\mathrm{HCl} .10 \mathrm{H}_2 \mathrm{O}\right.$ to $\left.\mathrm{HCl} .40 \mathrm{H}_2 \mathrm{O}\right)$ is $3.78 \mathrm{~kJ} \mathrm{~mol}^{-1}$.
B
Dissolution of gas in water is an endothermic process.
C
The heat of solution depends on the amount of solvent.
D
The heat of formation of HCl solution is represented by both (a) and (b).
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