Question

Show that, with appropriate coefficients, the two reactions can be summed to give the overall oxidation of SO2 by O2 to give SO3. Give the equation for the final overall oxidation of SO2 by O2 to give SO3 as your answer.

Answer 1

Explanation:

It is known that the oxidation of $SO_{2}$ to $SO_{3}$ is catalyzed by $NO_{2}$ . In this process, two steps are involved as follows.

(a)    $NO_{2}(g) + SO_{2}(g) \rightarrow NO(g) + SO_{3}(g)$

whereas, the second step is

(b)    $2NO(g) + O_{2}(g) \rightarrow 2NO_{2}(g)$

Balancing the above reaction by multiplying equation (a) by 2 as follows.

(c)    $2NO_{2}(g) + 2SO_{2}(g) \rightarrow 2NO(g) + 2SO_{3}(g)$

Now, on adding both  reaction equations (b) and (c) the net reaction equation will be as follows.

        $2SO_{2}(g) + O_{2}(g) \rightarrow 2SO_{3}(g)$

Thus, we can conclude that the equation for the final overall oxidation of $SO_{2}$ by $O_{2}$ to give $SO_{3}$ is as follows.

             $2SO_{2}(g) + O_{2}(g) \rightarrow 2SO_{3}(g)$