The rate of formation of $S{O}_3$ in the reaction $2S{O}_2+O_2\to 2S{O}_3$ is $50g{\min }^{-1}.$ Hence, rate of disappearance of $O_2$ is                         

For the given reaction,

$2S{O}_2+O_2\to 2S{O}_3$

Given,

The formation of $S{O}_3=50g/\min$

The rate of disappearance of $O_2$ =?

Rate equation,

$\frac{d{O}_2}{dt}=\frac{1}{2}\frac{dS{O}_3}{dt}=\frac{1}{2}\times \frac{50}{80}mole$

$=\frac{1}{2}\times \frac{5}{8}$ moles of oxygen

$=\frac{5}{16}\times 16\times 2g{\min }^{-1}$=10gram/min