Acidic oxide Some non-metal oxides, such as nitrous oxide (NO) and carbon monoxide (CO), do not display any acid/base characteristics. Acidic oxides can also react with basic oxides to produce salts of oxoanions: Acidic oxides are environmentally relevant. Sulfur and nitrogen oxides are considered air pollutants as they react with atmospheric water vapour to produce acid rain. Although it is difficult to classify these oxides as acids, the property is manifest in reactions with bases. For example, carbon dioxide reacts with alkali. For this reason, alkali is kept in stoppered vessels to inhibit reaction with atmospheric carbon dioxide. In geochemistry complex silicates
Sulfur dioxide and 2002. This improvement resulted in part from flue-gas desulfurization, a technology that enables SO to be chemically bound in power plants burning sulfur-containing coal or oil. In particular, calcium oxide (lime) reacts with sulfur dioxide to form calcium sulfite: Aerobic oxidation of the CaSO gives CaSO, anhydrite. Most gypsum sold in Europe comes from flue-gas desulfurization. Sulfur can be removed from coal during burning by using limestone as a bed material in fluidized bed combustion. Sulfur can also be removed from fuels before burning, preventing formation of SO when the fuel is burnt. The Claus process is used in