Oct. 15, 1921 



Hydrocyanic Acid in Sudan Grass 



135 



This shows that the use of hot acid is similar to that of hot water and 

 that acid has no power to spht off the hydrocyanic acid, at least in the 

 concentration used. The traces obtained in some cases were no doubt 

 due to liberation of hydrocyanic acid during maceration. It would, 

 appear, however, that hot water was less destructive than hot acid. 

 I/ike experiments with hydrochloric acid were performed with similar 



results. ,,^.. ^.r>{' .r..>!!;.-:i r..,^ 



On July 2 1 eight samples were prepared and digested at room tempera- 

 ture in phosporic acid (Table XIV) . 



Table XIV. — Effect 0/ phosphoric acid on liberation of hydrocyanic acid 



H3PO4 added. 



Nji.. 

 NI0.5 

 NI0.2 

 Njo.i 



HCN ob- 

 tained. 



Mgm. 



H3PO4 added. 



NI0.05 

 N 1 0.02 

 Njo.oi 

 Water. 



HCN ob- 

 tained. 



Mgin, 



The results indicate that the inhibiting power of phosphoric acid 

 (H3PO4) was somewhat less than that of hydrochloric (HCl) or sulphuric 

 acid. This would be expected since the degree of ionization of phosphoric 

 acid is less than that of hydrochloric or sulphuric acid. Experiments 

 with tartaric acid gave similar results. 



EFFECT OF DIGESTING IN ALKALINE SOLUTION 



On July 20, 16 samples were prepared and digested in sodium-hydroxid 

 (NaOH) and sodium-carbonate (Na2C03) solutions, respectively (Table 

 XV). 



Table XV. — Effect of alkaline solution on formation of hydrocyanic acid 



NaOH added. 



Nji. .. 

 NI0.5. 



NjO.2. 



NIo.i. 

 Njo.05 

 N 1 0.02 

 Njo.oi 

 Water. 



HCN 

 obtained. 



Mgm. 



19 



Nas CO3 added. 



Nil... 

 NI0.5. 

 NI0.2. 

 NIo.i . 

 NI0.05 

 NI0.02 

 NIo.oi 

 Water . 



HCN 

 obtained. 



Mgm. 



o 



o 



o 



o 



Trace. 



17 



17 



20 



The results show the same general effect as that secured with acid 

 solutions. 



