Sulfurous acid is primarily used in the bleaching of various materials, including paper and textiles, where it helps to remove unwanted colors and impurities. It is also employed in the preservation of foods and beverages, particularly in the wine-making process, where it acts as an antioxidant and antimicrobial agent to extend shelf life and maintain freshness. In water treatment, sulfurous acid is utilized to dechlorinate water, making it safer for discharge into the environment. Additionally, it serves as a reducing agent in chemical reactions, aiding in the synthesis of various compounds. Its disinfectant properties make it valuable in sanitizing equipment and surfaces in industrial settings.