ISOLATION OF PURE POTASSIUM NITRITE FROM THE COMMERCIAL SUBSTANCE

Fairly appreciable quantities of pare potassium nitrite have been isolated from the Merck's pure potassium nitrite containing about 92% of the substance. When a concentrated aqueous solution of the substance is cooled in a freezing mixture of ice and ammonium chloride pure nitrite or mixtures of nitrite and nitrate richer in nitrite than the original substance crystallises out so that pure nitrite becomes separated on fractional crys.

The melting point of the substance and its degrees of dissociation are ascertained and the solubility of the substance at the melting point of ice and the cryohydric point of ice and ammonium chloride are determined.