Which of the following is the amount in grams of sodium carbonate$\left(N{a}_{2}C{O}_3\right)$ which contains $16\mathit{ g}$ of oxygen?

$1 \mathrm{mole}$ of sodium carbonate $\left(N{a}_{2}C{O}_3\right)$ has a mass of
$\Rightarrow 2\times 23+12+3\times 16$
$\Rightarrow 106g$
Now, three oxygen atoms are present in sodium carbonate, so $48\mathit{ g}$ of oxygen is present in $106\mathit{ g}$ of $N{a}_{2}C{O}_3$
Therefore, $16\mathit{ g}$ of oxygen is present in
$\Rightarrow \frac{106}{48}\times 16$
$\Rightarrow 35.3\mathit{ g}$ of $N{a}_{2}C{O}_3$

Therefore, $35.3\mathit{ g}$ of sodium carbonate contains $16\mathit{ g}$ of oxygen.