posted by ESPINE .
Describe an experimental method for the estimation of oxalate in the product, potassium trioxalatoaluminate(III)
I would think the easiest way is to decompose the compound and measure the loss in weight due to the loss of CO2.
Weigh a known mass of the compound, dissolve it in distilled water; add a saturated solution of Sodium hexanitrocobaltate(II) to precipitate all the potassium ions. From the mass of the precipitated K3[Co(NO2)3], the K+ can be determined.