352 G. S. Jamieson — Determination of Hyd, 



razine. 



Art. XXXII. — A Volumetric Method for the Determination 

 of Hydrazine i by George S. Jamieson. 



A method for the determination of hydrazine has been 

 described by Rimini* and recently tested farther by Hale and 

 E-edfield.f This is based upon the oxidation of the hydrazine 

 compound in aqueous solution by the addition of an excess of 

 standard potassium iodate solution, according to the following 

 equation : 



5(lSr 2 H 4 .H 2 S0 4 ) + 4KI0 3 = 5N 2 + 12H 2 + 2l 2 + 2K 2 S0 4 + 3ll 2 S0 4 



The liquid is then boiled until the iodine is expelled and the 

 excess of potassium iodate is found after cooling by adding 

 potassium iodide, acidifying with sulphuric acid, and titrating 

 with sodium thiosulphate solution. The chief objection to this 

 method, according to Hale and Redfield, is the. length of time 

 required for the analysis. 



The method to be described here is based upon the titration 

 of hydrazine by potassium iodate in a strong hydrochloric acid 

 solution, according to the general method of L. W. Andrews.4; 

 It has the advantages of being rapid, and requiring the use of 

 only a single, very stable volumetric solution. Besides, as will 

 be seen from the results that follow, it is very accurate. 



In order to test the method, a solution containing 3*567 g. of 

 KI0 3 in 1000 cc was prepared. According to the equation of 

 the expected reaction 



N 2 H 4 .H 2 S0 4 + KI0 3 + 2HC1 = X 2 + IC1 + 3H Q 0-|-KC1 + H 2 S0 4 



the equivalent of this solution is l cc = -002169 g. X 2 H 4 .H 2 S0 4 

 and l cc = '000534: g. X 2 H 4 . Weighed portions of pure hydra- 

 zine sulphate were placed in a 250 cc glass stoppered bottle 

 together with 20 cc of water, 30 cc of hydrochloric acid and 6 CC 

 of chloroform. Then the potassium iodate solution was run 

 in gradually, with shaking between the additions, until the 

 chloroform, after increasing and then diminishing in color, was 

 just decolorized. The following results were obtained : 





N 2 H 4 .H 2 S0 4 





N 2 H 4 .H 2 S0 4 







taken 



KIO3 used 



found 



Error 



I 



•0487&- 



22-5 cc 



•0488 = 



+ •0001 



II 



•0434 



19*9 



•0432 



— •0002 



III 



•0589 



27*3 



•0592 



+ •0003 



IV 



•0472 



21-9 



•0475 



+ •0003 



V 



•0986 



45-65 



•0990 



+ -0004 



VI 



•1060 



49'00 



•1063 



+ •0003 



*" Ga?z. chitn. ital., xxix, I, 265, 1899. 



) Journ. Amer. Chern. Soc, xxxiii, 1362, 1911. 



X Journ. Amer. Chem. Soc, xxv, 756,1903. 



