Question

Substances $X$ and $Y$ are colorless gases obtained by combination of sulphur and oxygen. Substance $X$ results from combination of $6.00g$ of sulphur with $6.00g$ of oxygen and substance $Y$ results from combination of $8.60g$ of sulphur with $12.9g$ of oxygen. If the number of moles of oxygen in X were $10$, what would be the number of moles of oxygen in Y?

Answer 1

Ratio
$S$ $O$
$X:S{O}_2$ $1:1$ mass ratio
$1:2$ mole ratio
$Y:S{O}_3$ $2:3$ mass ratio
$1:3$ mole ratio

Thus, $O$ atom is in $S{O}_2$ and $S{O}_3$ are simple multiple of each other.

$10$ moles in $X\equiv \frac{3}{2}\times 10$ moles in $Y$

Thus, there will be 15 moles in Y.