Sulfur dioxide is an economically important gas that is used as a refrigerant, disinfectant, and reducing
atmosphere for preserving food. Although it is also used in the manufacture of many other sulfur compounds, the most important use of SO 2 is as a precursor in producing sulfuric acid. It can be obtained
by burning sulfur, but it is also produced in numerous other reactions. Sulfites react with acids by liberating SO 2 .