Barium acetate ferrocyanide

Sulphates, Copper, and Alkalies. — Boil for a few minutes a solution of 5 gm. of ferrous chloride in 10 cc. of water and 5 cc. of nitric acid (sp. gr. 1.3), dilute to 120 cc., add 20 cc. of ammonia water, and filter evaporate 50 cc. of the filtrate and ignite the residue. The weight of the latter should not exceed 0.001 gm. Slightly acidulate 20 cc. of the filtrate with hydrochloric acid and add barium nitrate solution. No change should appear. 20 cc. of the filtrate acidified with acetic acid should show no change upon addition of potassium ferrocyanide solution. 

The acid filtrate is treated with excess of ammonium chloride and with ammonia to precipitate the ferric oxide and any alumina, the precipitate being tested for the latter in the usual way. The filtrate is divided into three parts one is acidified with acetic acid and tested for copper with ferrocyanide in another the manganese (if present) is precipitated with ammonium sulphide, lime and magnesia being then tested for in the third sulphates are tested for with barium chloride. Manganese is best sought in a separate portion of the substance by the well-known dry reaction. 

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