The given chemical reaction is a multi-step process involving the conversion of sulfur to sulfur dioxide (SO2) to sulfur trioxide (SO3) to sulfuric acid (H2SO4) and back to sulfur dioxide (SO2).

It starts with the oxidation of sulfur to sulfur dioxide, which is represented by the equation: S + O2 → SO2.

Then, sulfur dioxide is further oxidized to sulfur trioxide in the presence of a catalyst, typically vanadium pentoxide: 2SO2 + O2 → 2SO3.

Next, sulfur trioxide reacts with water to form sulfuric acid: SO3 + H2O → H2SO4.

Finally, sulfuric acid can be dehydrated to form sulfur trioxide, which can further decompose back to sulfur dioxide and oxygen: H2SO4 → SO3 + H2O → SO2 + O2.

Overall, this multi-step process involves the conversion of sulfur to sulfur dioxide to sulfur trioxide to sulfuric acid and back to sulfur dioxide.