An example of a tribasic acid is phosphoric acid, H PO , and here we may have three different classes of salts of three various degrees of basicity or base-saturation. We may have the first step of basicity due to combination with soda, NaH PO , or monosodium phosphate, the second step, Na HPO , or disodium phosphate, and the third, and final step, Na PO , or trisodium phosphate.
What volume of a solution of sodium hydrogen phosphate, containing 90 grams of Na HPO .12H O per liter, would be required to precipitate the zinc as ZnNH PO and what weight of precipitate would be obtained? A sample of magnesium carbonate, contaminated with SiO as its only impurity, weighs 0.5000 gram and loses 0.1000 gram on ignition. !Answer!: 9.07 cc.