What happens when Sulphur dioxide reacts with Oxygen?
Answer: Aqueous solution of H2S becomes turbid in presence of air. When an aqueous solution of H2S is exposed to open air, the oxygen in the air slowly oxidizes the solution to form sulphur. As the resulting sulfur mixes with the solution, the solution becomes turbid.
2H2S + O2 = 2H2O + 2S ↓