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

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.

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

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
$10(100 \mathrm{x}+y+z)$
3
JEE Main 2025 (Online) 4th April Evening Shift
MCQ (Single Correct Answer)
+4
-1

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).
4
JEE Main 2025 (Online) 4th April Morning Shift
MCQ (Single Correct Answer)
+4
-1

One mole of an ideal gas expands isothermally and reversibly from $10 \mathrm{dm}^3$ to $20 \mathrm{dm}^3$ at 300 K . $\Delta \mathrm{U}, \mathrm{q}$ and work done in the process respectively are

Given: $\mathrm{R}=8.3 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}$

$\ln 10=2.3$

$\log 2=0.30$

$$\log 3=0.48$$

A
$0,21.84 \mathrm{~kJ},-1.726 \mathrm{~J}$
B
$0,21.84 \mathrm{~kJ}, 21.84 \mathrm{~kJ}$
C
$0,1.718 \mathrm{~kJ},-1.718 \mathrm{~kJ}$
D
$0,-17.18 \mathrm{~kJ}, 1.718 \mathrm{~J}$
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