Overview of the content: attempt to prepare sodium dicyanite by reducing sovium bisulfite with zinc powder in water, forming a zinc hydroxide-containing paste; after heating to about 45 °C, mixture is cooled and filtered to yield a sodium dicyanite solution (roughly 60 mL filtrate) with minor bisulfite and thiosulfate; the filtrate can be dehydrated with absolute ethanol to give a crystalline solid (~8 g) with a potential yield up to ~32 g from the full filtrate (about 63%), though the solid is unstable and heats up in air; the solid reacts with acids (sulfuric acid releases sulfur dioxide; nitric acid oxidizes vigorously); in solution the sodium dicyanite is stabilized by a slightly alkaline pH and can be used as a reducing agent directly.
more