Answer:
See explanation
Step-by-step explanation:
We know that the process of the oxidation of SO2 to SO3 is catalysed by NO2 gas. It occurs in two stages and i will show the balanced reaction equation of the both stages below;
Step 1
2NO2(g) + 2SO2(g) ------> 2NO(g) + 2SO3(g)
Step 2
2NO(g) + O2(g) -------> 2NO2(g)
So, the overall reaction equation is;
2SO2(g) + O2(g) ------> 2SO3(g)