Dithionite
The dithionite anion, is an oxoanion of sulfur. It is commonly encountered as colorless salts.Reactions
Dithionite is a reducing agent. At pH 7, the potential is −0.66 V vs NHE. Redox occurs with formation of sulfite:
Dithionite undergoes acid hydrolytic disproportionation to thiosulfate and bisulfite:
It also undergoes alkaline hydrolytic disproportionation to sulfite and sulfide:
It is formally derived from dithionous acid.finds widespread use in industry as a reducing agent.
Dithionite is used in conjunction with complexing agent to reduce iron oxy-hydroxide into soluble iron compounds and to remove amorphous iron-bearing mineral phases in soil analyses.
The decomposition of dithionite produces reduced species of sulfur that can be very aggressive for the corrosion of steel and stainless steel. Thiosulfate is known to induce pitting corrosion, whereas sulfide is responsible for stress corrosion cracking.
