Question

Rate of formation of $S{O}_3$ in the following reaction $2S{O}_2+O_2\to 2S{O}_3$ is $100g$ $mi{n}^{-1}$.

Then the rate of disappearance of $O_2$ is:

• A. $50g$ $mi{n}^{-1}$
• B. $40g$ $mi{n}^{-1}$
• C. $200g$ $mi{n}^{-1}$
• D. $20g$ $mi{n}^{-1}$

Answer 1

The correct option is D $20g$ $mi{n}^{-1}$

$2{SO}_2+O_2\to 2{SO}_3$

Rate, r $=-\frac{1}{2}\frac{\left[{△SO}_2\right]}{△t}=-\frac{△\left[O_2\right]}{△t}=\frac{1}{2}\frac{△\left[{SO}_3\right]}{△t}$

$\frac{1}{2}\times$ rate of formation of ${SO}_3=$ rate of disappearance of $O_2$

$\frac{1}{2}\frac{△\left[{SO}_3\right]}{△t}=-\frac{△\left[O_2\right]}{△t}$

$-\frac{△w_{O_2}}{△t}=\frac{1}{2}\times \frac{100}{80}\times 32g.{min}^{-1}=20g.{min}^{-1}$

So, the correct option is $D$