sodium hydrosulfite
noun Chemistry.
a white, crystalline, water-soluble powder, Na2S2O4, used as a reducing agent, especially in dyeing, and as a bleach.
Also called
hydrosulfite,
so·dium di·thi·o·nite
[dahy-thahy-uh-nahyt] /daɪˈθaɪ əˌnaɪt/,
sodium hyposulfite.