Another unknown was tested using this procedure. Upon theaddition of 6M NH3 and 6M HNO3, no precipitate formed. (NH4)2CO3was then added. A precipitate formed and the mixture wascentrifuged and decanted. The liquid was then transferred to asmall beaker and heated to dryness. Once cool, 1M H3PO4 and 1MNa2HPO4 were added to re-dissolve the solid, and the solution wasdivided into two test tubes. To the first, solid KI was added; nochange was observed. To the second, HDMG was added; a redprecipitate formed. The solid from the centrifugation was thendissolved in 6M HCl and Na2SO4 was added. A white precipitateformed. The mixture was centrifuged and decanted. 6M NH3 and(NH4)2C2O4 were added to the liquid. A white precipitate formed.Which cations are present in the unknown?
