Gives $0.7938\,g\,CO _{2}=0.018$ moles
$0.4428\,g\,H _{2} O =0.0246$ moles
So moles of $C =0.018 \Rightarrow 0.216\,g$
Moles of $H =0.049 \Rightarrow 0.049\,g$
$\therefore$ wt. of Oxygen $=0.492-0.216-0.049$
$\%$ of Oxygen $=\frac{0.227}{0.492} \times 10046$ (approx.)
(મોલર દળ $N _{2}=28 \,g\, mol ^{-1}$, $STP$ એ $N _{2}$નું મોલર કદ $: 22.4\,L$)