In ${\text{SO}}_{\text{2}}$, the mass of sulphur in combination with 3.0 g of oxygen is

The stoichoimetric balanced chemical equation for the preparation of ${\text{SO}}_{\text{2}}$ is

            $\text{S\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}}+{\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}O}}_2\to {\text{\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}\hspace{0.17em}SO}}_{\text{2}}$

32g of Sulphur reacts with 32g of Oxygen to give 64g of ${\text{SO}}_{\text{2}}$.

Hence, the mass of Sulphur required to react with 3g of Oxygen is

$\frac{\text{32g\hspace{0.17em}of\hspace{0.17em}S}}{{\text{32g\hspace{0.17em}of\hspace{0.17em}O}}_{\text{2}}}\times {\text{3.0g\hspace{0.17em}of\hspace{0.17em}O}}_{\text{2}}=\text{3.0\hspace{0.17em}g\hspace{0.17em}of\hspace{0.17em}S}$

.