In methane combustion, if 2.5*mol O_2 were present, what molar quantity of methane would react?

$C {H}_{4} \left(g\right) + 2 {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right) + 2 {H}_{2} O \left(g\right)$. So $1.25$ $m o l$ methane are necessary for the given quantity of dioxygen.
$C {H}_{4} \left(g\right) + 2 {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right) + 2 {H}_{2} O \left(g\right)$.
This equation clearly tells us that each mole of methane requires 2 mole of dioxygen for complete combustion. There are $2.5$ $m o l$ ${O}_{2}$; if complete combustion occurred, then $1.25$ $m o l$ methane gas were combusted.