An aqueous solution of lead II phosphate is added to an aqueous solution of potassium iodide. When the two colorless solutions mix, a bright yellow precipitate forms in a double replacement reaction. What is the balanced chemical equation?

1 Answer
Jan 15, 2016

#PbHPO_4(aq) + 2KI(aq) rarr PbI_2(s)darr + KH_2PO_4#


This question is unfortunate as phosphate salts tend to be as soluble as bricks, and lead phosphate, #Pb_3(PO_4)_2# would be even more insoluble. Thus I have assumed a biphosphate salt; #HPO_4^(2-)# can have some solubility (at any rate phosphate ion, #PO_4^(3-)#, is fairly rare, and speciates to #HPO_4^(2-)# in aqueous solution).