Sodium hydrosulfite is a versatile chemical that's used in the manufacture of a variety of products we all use every day, from photographic film to wine; from fine writing papers to leather goods; from colored fabrics to metal recovery.

While the applications for this chemical workhorse are as vast and as varied as the industries that use it, in most cases, sodium hydrosulfite performs one of the following three roles:

• As a reducing agent, hydrosulfite chemically reduces other components by donating an electron or electrons
• As a sulfonating agent, hydrosulfite adds sulfur to another chemical compound
• As a cation source, hydrosulfite adds a cation, or sodium, to a product system

Sodium hydrosulfite is the common commercial name for products containing sodium dithionite, Na₂S₂O₄, as the active ingredient.

Some industries that commonly rely on sodium hydrosulfite in the manufacture of their products include:

• Textiles
• Pulp and paper
• Clay
• Leather
• Foods and beverages
• Polymers
• Photographics
• Chemical processing
• Cleaners
• Water treatment
• Gas purification
• Environmental improvement