Q.
For the reaction
$CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(l)$
$\Delta H^°_f\, of\, CH_4(g), CO_2(g)\, and\, H_2O(l)$ is respectively -x, -y and -z kJ $mol^{-1}$. Enthalpy change $(∆_r^°H)$ for the reaction is
Solution: