Oxide from Cerous Oxalate

If it is assumed that Pb203 and Pb304 are lead metaplumbate and lead orthoplumbate, respectively, write formulas to express these facts. Write the formulas of the corresponding meta- and orthoplumbic acids. 

Warm a little of the red lead with nitric acid. What is the residue, and what soluble salt is formed Filter the mixture and test the filtrate by diluting and adding a few drops of sulphuric acid. 

Heat a little of the red lead to a dull red heat on a thin piece of iron. 

Ceric Oxide from Cerous Oxalate, Ce02 

Cerous oxalate, Ce2(C2O4)3-10H2O, is formed in the Welsbach treatment of Monazite sands in the production of thorium nitrate, and is the starting point in the preparation of nearly all cerium salts. Since ceric oxide is more easily acted upon by common reagents, it is often prepared as the first step in making other salts from the oxalate. 

---

Iron-gray, ductile, malleable metal face -cen tered cubic structure at room temp. Stable in dry air, but superficially oxidized in moist air when finely divided may ignite sponta -neously. d 6.77. mp 795". E (aq) Cei+ /Ce — 2,48 V (calc). Slowly dec by cold, rapidly by hot water sol in dil mineral adds. Ceric salts usually are yellow to orange-red in color tnd liberate iodine from KI. Cerous salts are usually white tnd give a white ppt with alkali hydroxides or sulfides, insol ineicess of reagent they also are pptd by ammonium oxalate from cold dil acid sols. 

---