a salt of chlorous acid, HClO2. Chlorites are formed in the reaction of chlorine dioxide and alkaline solutions in the presence of H2O2 or reducing agents; for example,
2ClO2 + 2NaOH + H2O2 = 2NaClO2 + 2H2O + O2
In acidic media, chlorites are good oxidizing agents; in the solid state, they explode upon impact or upon heating, as well as in the presence of readily oxidizable impurities.
Of all the chlorites, sodium chlorite has found use. It is obtained as colorless crystals, whose solubility in water is 31.1 percent at 0°C, 50.7 percent at 37.4°C, and 56.3 percent at 70°C. Below 37.4°C, it forms the crystal hydrate NaClO2 · 3H2O. Above 100°C, it begins to decompose, forming sodium chlorate and sodium chloride. Upon reaction with chlorine, it forms ClO2 and NaCl. Sodium chlorite is used in the form of aqueous solutions for the mild bleaching of fabrics (mainly linens) and paper, for water decontamination, and, in small amounts, for the production of ClO2.