Sulphur dioxide

Sulfur (IV) oxide has the name, also officially used in the chemical science - sulfur dioxide, in addition, this substance is also called sulfur dioxide or sulfurous anhydride. Sulfur (IV) oxide under normal conditions is a gas that does not have a color, with a peculiar, unpleasant odor that resembles the smell of a match at the time of its ignition.

The gas liquefies when the pressure rises, while the temperature can not differ from the usual room temperature. The substance is soluble in water to produce an unstable sulfurous acid. The degree of solubility in water of sulfur dioxide is at a temperature of 20 C 11.5 grams of substance per 100 grams of water. It is interesting that when the temperature rises, the level of solubility of the compound decreases. In addition to water, sulfurous anhydride is soluble in ethanol and sulfuric acid. In nature, sulfur dioxide, whose formula is SO2, is one of the elements that make up volcanic gases.

The industrial production of sulfurous anhydride is based on direct combustion of sulfur, it is also possible to produce this gas by calcining sulphides, especially such as pyrite.

Sulphurous gas is also obtained by laboratory means. For this purpose, an effect is exerted on the sulfites of strong acids. As the main substance in laboratories also use hydrosulphites. Such a reaction has the form of the equation: Na2SO3 + H2SO4 → Na2SO4 + H2SO3. The result of the reaction, as can be seen from the equation, is sulfuric acid, which, due to its instability, immediately decomposes into sulfur dioxide and water.

Less commonly, for obtaining a substance, a method is used in which low-active metals are exposed to dilute sulfuric acid, and the reaction must proceed with the heating of the working solution.

The main chemical properties of sulfurous anhydride are as follows.

Sulfur gas is absorbed in the ultraviolet range of the spectrum. It is classified as an acid oxide. As already noted, sulfur dioxide is soluble in water during a reversible chemical reaction.

When the gas enters the reaction with alkali, sulfites are obtained. In general, if we characterize the chemical activity of this gas, it should be recognized as quite high. During the reactions, the reducing properties of the substance are most often manifested, and the oxidation level of sulfur, when reactions proceed, becomes higher.

Oxidizing properties of sulfur dioxide is manifested when carrying out reactions accompanied by strong reducing agents. For example, in the industrial sector, the method used to obtain sulfur is applied by its reduction with carbon monoxide (II).

Sulfur (IV) oxide in the chemical industry is used mainly for the production of sulfuric acid. In general, its application is very broad and ambiguous. The fact is that sulfur dioxide is toxic. When it is inhaled, you can get poisoning, the symptoms of which are perspiration in the throat, runny nose, cough. By inhalation, sulfur dioxide harms the more the concentration of the substance was higher. At high concentrations, severe consequences can occur, including choking, speech disorders and pulmonary edema.

Sulfur (IV) oxide is used in the food industry, in particular it is present in low-alcohol beverages as a preservative. In textile production it is used as a component of bleaching agents for various materials that can not be bleached with chlorine compounds.

In industrial and scientific laboratories, sulfur (IV) oxide acts as an indispensable solvent, but in this case it should be remembered that the gas can contain impurities of water and SO3, which can affect the purity and correctness of the reaction flow in the presence of dioxide. Therefore, in these cases, the gas is first purified by passing through a filter with a concentrated H2SO4 content, necessarily in a closed vessel.

Because of its extensive use, sulfurous anhydride acts as one of the main pollutants of the atmosphere. Especially dangerous are the emissions resulting from the burning of the energy resources that we are familiar with - coal, natural gas and oil. As a rule, most of the harmful effects are through precipitation, because rainwater is the final product of the presence of the substance in the aerosol form.

At present, the highest concentration of this gas is observed in the northern hemisphere of the Earth, primarily over the USA, Ukraine, Western Europe and in the western regions of Russia.