Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. Excerpt from book: Section 3The conditions thus shown for the titration of antimony by this method are within rather narrow limits and are as follows: To .2000 gram of antimony (metallic) dissolved and oxidized by nitric acid and hydrochloric acid, or potassium chlorate and hydrochloric acid. The solution is then concentrated to about 50 c.c. This solution would be about 20 per cent. hydrochloric acid. To this must be added about 15 c.c. to 20 c.c. of concentrated hydrochloric acid, and the whole diluted to 600 c.c. or 700 c.c. Three grams of crystals of potassium iodide are then added, the liberated iodine titrated nearly to the end, I c.c. of starch solution introduced and the titration completed, textit{i. e., to no blue color. End point is very sharp. Having determined what seemed to be favorable conditions for this titration, a large number of determinations of antimony were made. A weighed portion of metallic antimony was taken, 1 to 2 c.c. of concentrated nitric acid and 50 c.c. or more of concentrated hydrochloric acid added, then boiled until the chlorine was partially removed, portions of i/ gram or less of potassium chlorate then added and free chlorine boiled out. Finally more hydrochloric acid was added and the solution concentrated to 50 c.c. or 60 c.c. The other conditions as to dilution, amount of potassium iodide added were as above given. The use of nitric acid and potassium chlorate would seem to be the strongest oxidizing mixture we have, so in most subsequent experiments the two were used, though the results of titration were the same if only nitric acid were used. It is desirable to use a small amount of nitric acid in every case, however, as metallic antimony dissolves very slowly in potassium chlorate and concentrated hydrochloric acid alone. The results of a large number of titrations were found to ...