1
JEE Main 2023 (Online) 1st February Evening Shift
Numerical
+4
-1

$$0.3 \mathrm{~g}$$ of ethane undergoes combustion at $$27^{\circ} \mathrm{C}$$ in a bomb calorimeter. The temperature of calorimeter system (including the water) is found to rise by $$0.5^{\circ} \mathrm{C}$$. The heat evolved during combustion of ethane at constant pressure is ____________ $$\mathrm{kJ} ~\mathrm{mol}{ }^{-1}$$. (Nearest integer)

[Given : The heat capacity of the calorimeter system is $$20 \mathrm{~kJ} \mathrm{~K}^{-1}, \mathrm{R}=8.3 ~\mathrm{JK}^{-1} \mathrm{~mol}^{-1}$$.

Assume ideal gas behaviour.

Atomic mass of $$\mathrm{C}$$ and $$\mathrm{H}$$ are 12 and $$1 \mathrm{~g} \mathrm{~mol}^{-1}$$ respectively]

2
JEE Main 2023 (Online) 1st February Morning Shift
Numerical
+4
-1

At $$25^{\circ} \mathrm{C}$$, the enthalpy of the following processes are given :

$$\mathrm{H_2(g)+O_2(g)}$$ $$\to$$ $$2\mathrm{OH(g)}$$ $$\mathrm{\Delta H^\circ=78~kJ~mol^{-1}}$$
$$\mathrm{H_2(g)+\frac{1}{2}O_2(g)}$$ $$\to$$ $$\mathrm{H_2O(g)}$$ $$\mathrm{\Delta H^\circ=-242~kJ~mol^{-1}}$$
$$\mathrm{H_2(g)}$$ $$\to$$ $$\mathrm{2H(g)}$$ $$\mathrm{\Delta H^\circ=436~kJ~mol^{-1}}$$
$$\frac{1}{2}\mathrm{O_2(g)}$$ $$\to$$ $$\mathrm{O(g)}$$ $$\mathrm{\Delta H^\circ=249~kJ~mol^{-1}}$$

What would be the value of X for the following reaction ? _____________ (Nearest integer)

$$\mathrm{H_2O(g)\to H(g)+OH(g)~\Delta H^\circ=X~kJ~mol^{-1}}$$

3
JEE Main 2023 (Online) 31st January Evening Shift
Numerical
+4
-1
Enthalpies of formation of $\mathrm{CCl}_{4}(\mathrm{~g}), \mathrm{H}_{2} \mathrm{O}(\mathrm{g}), \mathrm{CO}_{2}(\mathrm{~g})$ and $\mathrm{HCl}(\mathrm{g})$ are $-105,-242,-394$ and $-92 ~\mathrm{kJ}$ $\mathrm{mol}^{-1}$ respectively. The magnitude of enthalpy of the reaction given below is _________ $\mathrm{kJ} ~\mathrm{mol}^{-1}$. (nearest integer)

$\mathrm{CCl}_{4}(\mathrm{~g})+2 \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g})+4 \mathrm{HCl}(\mathrm{g})$
4
JEE Main 2023 (Online) 31st January Morning Shift
Numerical
+4
-1

The enthalpy change for the conversion of $$\frac{1}{2} \mathrm{Cl}_{2}(\mathrm{~g})$$ to $$\mathrm{Cl}^{-}$$(aq) is ($$-$$) ___________ $$\mathrm{kJ} \mathrm{mol}^{-1}$$ (Nearest integer)

Given : $$\Delta_{\mathrm{dis}} \mathrm{H}_{\mathrm{Cl}_{2(\mathrm{~g})}^{\theta}}^{\ominus}=240 \mathrm{~kJ} \mathrm{~mol}^{-1}, \Delta_{\mathrm{eg}} \mathrm{H}_{\mathrm{Cl_{(g)}}}^{\ominus}=-350 \mathrm{~kJ} \mathrm{~mol}^{-1}$$,

$${\mathrm{\Delta _{hyd}}H_{Cl_{(g)}^ - }^\Theta = - 380}$$ $$\mathrm{kJ~mol^{-1}}$$