Standardization of permanganate solutions with sodium oxalate

Abstract

The titer of permanganate solut ions standardized with sodium oxalate by the procedure usually employed (McBride's) has been found to be too high when compared wit h the values obtained with other primary standards, the error in some cases being as much as 0.4 percent. However, by modifying this procedure the titer obtained with oxalate agrees satisfactorily with the values found with potassium dichromate, pure iron, and arsenious oxide. In the recommended procedure, 90 to 95 percent of the permanganate is added rapidly to a diluted sulphuric acid (5+95) solut ion of sodium oxalate at 25 to 30° C, the solution warmed to 55 to 60° C and titration completed as usual. Data are presented which show the effect on the new procedure of variations in acidity , t emperature, and other conditions.