colorless or white crystal(s) [MER06]
The monohydrate is a white crystalline solid; monoclinic structure; density 2.13 g/cm3; loses its water at about 160°C; converts to carbonate when ignited; effloresces in warm dry air; soluble in water, 33 g/100 mL at 20°C; a 0.05m solution of K2C2O4?2H2O has a pH 1.679.
Potassium oxalate, along with calcium oxalate, is found in leaves and roots of certain plants. It is used for cleaning and bleaching straw and for removing stains. It also is used in photography, in clinical tests, as a secondary pH standard, and in wet chemical analysis. The analytical application involves standardization of many oxidizing agents in titrimetric analysis.
Potassium oxalate can be preparaed by heating potassium formate at 360°C:
2HCOOK →K2C2O4+ H2
The salt is obtained as its monohydrate by neutralization of oxalic acid with a dilute aqueous solution of potassium hydroxide followed by crystallization:
H2C2O4+ 2KOH →K2C2O4+ 2H2O.
Flammability and Explosibility
Non flammable
Crystallise it from water below 50o. Dry it below 60o at 760mm. [See potassium oxalate above, Beilstein 2 IV 1823.]
