C. F. Roberts — Estimation of Chlorates and titrates. 233 



Weights taken. 



"Weights found. 



Difference. 



Potassium chlorate 



0-0500 



0*0515 



0-0015 



Potassium uitrate 



0-0500 



0-0494 



0-0006 



Potassium chlorate 



0-0500 



0-0508 



0-0008 



Potassium nitrate 



0-0500 



0-0493 



0-0007 



Potassium chlorate 



o-iooo 



0-0987 



0-0013 



Potassium nitrate 



o-iooo 



0-0995 



0-0005 



Potassium chlorate 



o-iooo 



0-1007 



0-0007 



Potassium nitrate 



o-iooo 



0-09S0 



0-0020 



Potassium chlorate 



0-0300 



0-0305 



0-0005 



Potassium nitrate 



o-iooo 



0-0990 



o-ooio 



Potassium chlorate 



o-iooo 



0-1006 



0-0006 



Potassium nitrate 



0-0300 



0-0293 



0-0007 



(2) 

 (3) 

 (*) 



(5) 

 (6) 



The method is simple, rapid, and easy, and sufficiently accu- 

 rate for most analytical work. One objection that may be 

 urged against it is that any error in the determination of the 

 nitric acid involves a corresponding error in the amount of 

 chloric acid, but the above results show that such errors will 

 be quite small if the experiment is conducted with proper pre- 

 cautions. 



It also appeared probable that a nitrate and nitrite could be 

 estimated at one operation in a somewhat similar manner. By 

 the action of manganous chloride on a mixture of nitric and 

 nitrous acids, nitric oxide and iodine would be set free from 

 each. Representing the weight of nitric oxide found by #, 

 and the weight of iodine found by b, and letting x equal the 

 amount of nitric acid operated upon, and y the amount of 

 nitrous acid, 



30 



30 



X 



63 



+ 4> v = 



- a, and 



379-5 

 63 



126- 

 47 



-y = b 



X — 



y- 



0-249 b- 

 2-35 a- 



-1-049 a 

 -0-186 b 



whence, 



In the attempt to verify these formulas by experiment, a 

 little difficulty was found in getting a pure and stable nitrite 

 upon which to operate. Some silver nitrite was prepared by 

 precipitation from potassium nitrite and silver nitrate. This 

 was washed well and dried as thoroughly as possible over sul- 

 phuric acid in the dark. Weighed portions were put in the 

 retort, and after the air was expelled, manganous chloride was 

 added. The amount of silver nitrate was then estimated from 

 the iodine set free in the bulbed tubes, and also from the nitric 



