Chemical lecture experiments . ustion of phosphorus. — Phosphorus burns inchlorine peroxide, and the combustion may bemade to proceed under water. Five grams of crystallized potassium chlorateare placed on the bottom of a 100 cc. cylinder or,better, of a test-tube on foot (Fig. 51). Fiftycubic centimeters of water are then added andtwo or three 2 mm. pieces of phosphorus arethrown into the water. A 10 cc. pipette is half filled with concentratedsulphuric acid and the tip thrust into the cylinderuntil it touches the potassium chlorate the acid comes in contact with the crystals, chl
Chemical lecture experiments . ustion of phosphorus. — Phosphorus burns inchlorine peroxide, and the combustion may bemade to proceed under water. Five grams of crystallized potassium chlorateare placed on the bottom of a 100 cc. cylinder or,better, of a test-tube on foot (Fig. 51). Fiftycubic centimeters of water are then added andtwo or three 2 mm. pieces of phosphorus arethrown into the water. A 10 cc. pipette is half filled with concentratedsulphuric acid and the tip thrust into the cylinderuntil it touches the potassium chlorate the acid comes in contact with the crystals, chlorineperoxide is evolved and the phosphorus burns. Test-tube on foot (Fig. 51) ; 10 cc. pipette ; crystallized KC103;2 mm. pieces of P. 37. Explosive combustion of alcohol in chlorine per-oxide. — A small quantity of chlorine peroxide is generatedin a 50 cc. cylinder according to the method in Ex. 33. Thecylinder is placed behind a glass screen and a few drops ofaleohol are allowed to fall from a test-tube into the gaseous. 104 CHEMICAL LECTURE EXPERIMENTS mixture. A sharp explosion occurs which is likely to blowsome of the acid out of the cylinder. Glass screen ; alcohol; C102 in cylinder. CHLORIC ACID 38. Preparation. — Sulphuric acid, when added to a solu-tion of barium chlorate, forms barium sulphate and chloricacid. Dilute sulphuric acid should be gradually added to a solu-tion of barium chlorate nntil the barium is completely pre-cipitated. On filtering off the liquid it will be found tocontain chloric acid and possess strong bleaching properties. Ba(C108)2 + H2S04 = BaS04 + 2 HC10S. Litmus; Ba(C103)2. PERCHLORIC ACID 39. Preparation. — Sulphuric acid reacts with pure potas-sium perchlorate, liberating perchloric acid. Five grams of chemically purepotassium perchlorate are heatedgently with 12 cc. of pure concen-trated sulphuric acid in a 100 retort (Fig. 52). Thepowder is placed in the flask and theconcentrated acid poured througha funnel, the introd
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