98 Mr. Everitt ofi the Beaction of Ferrocyanuret of Potassium 



tiire of the interchange which takes place during the process, 

 the more uniform and satisfactory are the results, and the more 

 do we economise our time, I have been induced to examine 

 very narrowly the above reaction. 



(2.) Assuming the composition of the crystallized yellow 

 ferrocyanuret of potassium to be 2 K Cy + Fe Cy + 3 Aq, 

 I find that on boiling it with sulphuric acid in a close vessel, 

 fths of the potassium remain in solution as bisulphate of po- 

 tassa, its cyanogen going off as hydrocyanic acid: the re- 

 maining :Jth combines as cyanuret of potassium with all the 

 cyanuret of iron to form a yellow insoluble salt : thus, 



2 proportions 



of the 



crystals. 



'3 Cy H. which escape as gas. 



r4K 



14 Cy 



(2¥e 



\2Cy 



6Aq 



with 



6S 



I 



3 (K-f- 2 S) bisulphate of potassa in so- 

 lution, 

 j 3 Aq— free. 

 Lk Cy+2 Fe Cy, which fall as yellow salt. 



Or in numbers : 

 2 proportions of salt. 



39- 15 X 4 potassium 

 28 X 2 iron 

 26-39 X 6 cyanogen 

 9x6 water 



Real 



sulphuric 



acid. 



40 X 6 



Results. 



3 (26-39 + 1) hydrocyanic acid. 

 3 (39-15 + 8)+ 6(40)bisulph.ofpot". 

 9x3 free water. 



(39-15 + 26-39) + 2 (28 + 2639) 

 yellow salt. 



Hence 



2 proportions of salt 212*47 X 2 = 

 6 proportions of sulphuric acid 40* X 6 = 



yield 



3 proportions of hydrocyanic acid 27*39 X 3 = 

 3 proportions of bisulph. of potassa 127*15 X 3 = 

 3 proportions of water 9*00 X 3 = 

 1 proportion of yellow salt K Cy 65*54 + 2 Fe \ __ 



Cy 108-78 / - 



424*94 

 240*00 



82-17 



381*45 



27*00 



174*32 



664*94 



664«94 



(3.) This was proved as follows : 



{a.) 212*5 grains of the crystals of ferrocyanuret of potas- 

 sium were dissolved in 2 fluid oz. of water, to which were 

 added 600 grains of dilute sulphuric acid of specific gravity 

 1*179, containing 20 per cent, of real acid, and therefore 

 amounting in all to 120 grains real acid ; the mixture was kept 

 boiling in a vessel partially closed to prevent the free ingress 

 of air, till the odour of hydrocyanic acid ceased to be given off: 



