Zinc lactate drugs test

① 5 mL of the solution (10 g/100 mL), ferrous lactate in a test tube, add bromine solution (20%) 1 mL and 0.5 mL dilute sulfuric acid (1 +10), placed in a water bath heated with a glass rod stir until yellow receded, add ammonium sulfate 4g mix, along the wall was gradually added dropwise 10% nitrous acid iron sodium cyanide and sulfuric acid solution 0.2 mL of concentrated ammonia solution 1 mL, the formation of two liquid layers. Place 30min, the two liquid layer at the interface appears a dark green ring.
② 5 mL of the solution (10 g/100 mL), plus a calcium lactate prepared solution of potassium ferrocyanide (10 g/100 mL), which happened a white precipitate separated precipitate insoluble in dilute hydrochloric acid.
③ 5 mL of the solution (10 g/100 mL), acidified with 10% sulfuric acid, add 1 drop of copper sulfate solution (1 g / L) and 5% solution of ammonium thiocyanate few drops of mercury, which produce purple precipitate .