EVOLUTION OP GASES PROM HOMOGENEOUS LIQUIDS. 



275 



Two other series of observations are given below, made under precisely the same 

 conditions of mass of salt, concentration of acid, and with slight differences of 

 temperature. 



Decomposition of Potassium Ferrocyanide by Sulphuric Add. 

 K 4 Fe(CN) 6 , SI^O + 6H 2 SO 4 + 3H 2 = 6CO + 2^80^ + 3(NH t ) a SO 4 + FeSO*. 



Experiments made in the earlier stages of this research on the rate of decomposition 

 of potassium ferrocyanide with concentrated sulphuric acid in accordance with the 

 above equation also illustrate this phenomenon of initial acceleration. The twin (J- 

 tube method was used, but the standard quantity of air taken was such as would 

 correspond to the decomposition of '058 gram of the salt. 



A mixture was made up as follows : 



21 grams crystallised ferrocyanide, corresponding to 860 observations. 

 420 . . . sulphuric acid. 

 27 water. 



This mixture was heated until the salt had completely dissolved in the acid to 

 form a clear liquid, and then observations were commenced, little or no gas other 

 than small quantities of hydrocyanic acid being given off before the salt dissolved. 



Temperature 150'8-151. 



Intervals in minutes (reduced) required for evolution of 

 standard volume of carbonic oxide. 



7-27 

 6-43 

 6-72 

 6-36 



6-03 

 6-13 

 6-12 



6-18 

 6-16 

 5-73 

 5-63 



5-70 

 5-66 



These results are precisely similar to those given above. 



2 N 2 



