JEE Main 2025 — 22 January, Evening Shift — Question 46

Consider the following cases of standard enthalpy of reaction $\left(\Delta \mathrm{H}_{\mathrm{r}}^{\mathrm{o}}\right.$ in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)$

$\mathrm{C}_{2} \mathrm{H}_{6}(\mathrm{~g})+\frac{7}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_{2}(\mathrm{~g})+3 \mathrm{H}_{2} \mathrm{O}(\ell) \Delta \mathrm{H}_{1}^{\mathrm{o}}=-1550$

C (graphite) $+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{CO}_{2}(\mathrm{~g}) \Delta \mathrm{H}_{2}^{\mathrm{o}}=-393.5$

$\mathrm{H}_{2}(\mathrm{~g})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{H}_{2} \mathrm{O}(\ell) \Delta \mathrm{H}_{3}^{\mathrm{o}}=-286$

The magnitude of $\Delta \mathrm{H}_{\mathrm{f}_{2} \mathrm{H}_{6}(\mathrm{~g})}^{\mathrm{o}}$ is____ $\mathrm{kJ} \mathrm{mol}^{-1}$ (Nearest integer).