This is a problem I was trying to help some chem students with. This is all that was given. Ca(H2PO4)2 + NaOH(limited) → CaHPO4 + Will one hydrogen be neutralized on each dihydrogen phosphate to yield Na2HPO4 and water? This is my guess so that the two phosphate ions stay the same/get the same neutralization. It's hard to say what those four hydrogens and limited NaOH would actually make... Ca(H2PO4)2 + 2NaOH(limited) → CaHPO4 + Na2HPO4 + 2H2O They had another problem that was exactly the same but had Mg in place of Ca. Would that reaction be the same?