46 H. Gruener — Iodometric Determination of Nitrates. 



distilled before decomposition, whenever the original amount 

 was large. Nitric acid was accordingly tested for in the dis- 

 tillate, and to this end all the conditions of the experiment 

 were repeated, except that the receiver contained only water. 

 Of the nitrate 04 grm. and of the iodide 4 grm., twice the 

 amount theoretically necessary were put into the retort, and at 

 the end of the experiment the solution in the receiver was 

 boiled with hydrogen peroxide to decompose the hydriodic 

 acid and drive out the iodine, care being taken to keep enough 

 water to hold any nitric acid present. When all the iodine was 

 gone sodium carbonate was added, the solution evaporated and 

 the residue ignited and tested with a saturated solution of man- 

 ganous chloride in hydrochloric acid, as described in the pre- 

 vious paper above mentioned. By this means 0*0002 grm. 

 potassium nitrate are very easily detected in 10 cm 3 of solution. 

 Nitric acid was found in the distillate of this experiment as well 

 as in two others conducted with 0'2 grm. and - l grm. of the 

 nitrate respectively. The residues in the retorts of these three 

 tests showed no trace of nitric acid. 









Table II. 

















Sp. Gr. of 

















solution of 



Amount 









KN0 3 



KI 





phosphoric 



of sol. 



Error 



Error 





taken. 



taken. 



Found. 



acid. 



used. 



KN0 3 



HNO3 



Series 3 



















grm. 



grm. 



grm. 







grm. 



grm. 



18 



00500 



1- 



0-0500 



1-43 



17cm 3 



o-oooo 



o-oooo 



19 



0-0200 



0-5 



0-0201 



1-43 



17 



0-0001 + 



0-0001 + 



20 



0-0200 



1- 



0-0198 



1-43 



17 



0-0002 — 



o-oooi- 



21 



0-0250 



I- 



0-0250 



1-43 



17 



00000 



0-0000 



22 



0-0300 



1- 



0-0307 



1-43 



17 



0-0007 + 



00004 + 



23 



0-0300 



1- 



00312 



1-43 



17 



00012 + 



0-0007 + 



24 



0-0350 



1- 



0-0353 



1-43 



17 



0-0003 + 



0-0002 + 



25 



0-0400 



1- 



0-0409 



1-35 



20 



00009 + 



0-0006 + 



26 



0-0450 



1- 



00444 



1-35 



20 



0-0006- 



0-0004 — 



27 



00500 



1- 



0-0499 



1-37 



20 



o-oooi- 



o-oooi- 



Series 4 

















28 



0-0600 



1- 



0-0568 



1-37 



20 



0-0032- 





29 



0600 



1- 



0-0575 



1-37 



20 



0-0025- 





30 



0-0600 



1- 



0-0576 



1-37 



20 



0-0024- 





31 



0-0600 



2- 



0-0588 



1-37 



20 



0-0012- 





32 



0-0600 



2- 



0-0605 



1-37 



18 



0-0005 + 





33 



0-0700 



2- 



0-0708 



1-37 



18 



0-0008 + 





34 



0-0800 



2- 



0-0811 



1-37 



18 



0-0011 + 





35 



0-0900 



2- 



0-0842 



1-37 



18 



0-0058- 





36 



o-iooo 



2- 



0-0996 



1-37 



18 



0-0004- 





37 



o-iooo 



2- 



0-1012 



1-37 



18 



0-0012 + 





38 



o-iooo 



1-5 



0-0909 



1-37 



18 



0-0091 — 





39 



o-iooo 



2-5 



00979 



1-37 



18 



0-0021 — 





40 



0-1021 



3- 



0-1005 



1-43 



17 



0-0016 — 





41 



0-1032 



2' 



0-0949 



1-43 



17 



0-0085 — 





