For which reaction(s) is the $\mathrm{\Delta }H$ value close to the$\mathrm{\Delta E}$ value?

(P) $\begin{array}{r}{\mathrm{CH}}_4\left(g\right)+2{\mathrm{O}}_2\left(g\right)⟶\mathrm{CO}\left(g\right)+2{\mathrm{H}}_2\mathrm{O}\left(l\right)\end{array}$

(Q) $\begin{array}{r}{\mathrm{C}}_2{\mathrm{H}}_4\left(g\right)+3{\mathrm{O}}_2\left(g\right)\to 2{\mathrm{CO}}_2\left(g\right)+2{\mathrm{H}}_2\mathrm{O}\left(g\right)\end{array}$

Reaction given in Q,

${\mathrm{C}}_2{\mathrm{H}}_4\left(g\right)+3{\mathrm{O}}_2\left(g\right)\to 2{\mathrm{CO}}_2\left(g\right)+2{\mathrm{H}}_2\mathrm{O}\left(g\right)$

For this reaction

$\mathrm{\Delta }{n}_g=0$

Thus, the change in enthalpy is equal to the change in energy.

$\Rightarrow \mathrm{\Delta }H=\mathrm{\Delta }E$