Mixter — Products of the Explosion of Acetylene. 301 



Experiment 1$. — Gas, 85 per cent of acetylene and 15 per 

 cent of nitrogen ; pressure, 3061 mm ; temperature, 17'8°. The 

 pressure after the explosion when the gas had cooled to 17° "8 

 was the same as before the explosion. Each of two tests for 

 acetylene in the residual gas gave 0'25 per cent. The residual 

 gas was passed slowly through an absorbing tube containing a 

 dilute solution of potassium hydroxide until the pressure in the 

 bomb had fallen to that of the atmosphere ; 20 co of a deci- 

 normal solution of silver nitrate were used in titrating the 

 solution of potassium hydroxide. Next 10 cc of a concentrated 

 solution of potassium hydroxide were poured into the bomb 

 to absorb the hydrocyanic acid remaining in it. The mixture 

 of carbon and potassium hydroxide was thoroughly shaken 

 and then washed on a filter. The filtrate required 14-4 0c of a 

 decinormal solution of silver nitrate, making the total amount 

 of the solution of silver used 34 - 4 cc , corresponding to - 1858 

 gram of hydrocyanic acid, or - ltiS8 gram and 139 - 6 CC (at 0° 

 and 760 mm ) per liter in the bomb. 



Experiment 1^3. — Gas, 76*6 per cent of acetylene and 23*4 

 per cent of nitrogen ; pressure 3818 mm at 14'8°. 1'7 per cent of 

 acetylene was found in the first portions of gas drawn from 

 the bomb and 2'5 per cent when the pressure was little more 

 than that of the atmosphere. The attempt to estimate the 

 hydrocyanic acid remaining in the bomb was unsuccessful. 

 An alcoholic solution of potash was used, as this wets the finely 

 divided carbon better than water. The filtered solution 

 became turbid on adding silver nitrate and the titration was so 

 unsatisfactory that the result was rejected. The solution of 

 potassium hydroxide used to absorb the gas drawn from the 

 bomb required in titrating 32'3 0C of a decinormal solution of 

 silver nitrate corresponding to 01747 gram of hydrocyanic 

 acid. As -|ths of the gas in the bomb were taken for this 

 determination we may assume that 0-1747 X f- = 0-2187 gram 

 was the total amount of hydrocyanic acid in the gas in the 

 bomb and not condensed on the carbon. This result calculated 

 for a volume of 1 liter gives - 200 gram and 165°° (at 0° 

 and 760 mm ) of hydrocyanic acid. The gas after the explosion 

 was alkaline to litmus and the solution of potassium hydroxide 

 gave off ammonia on warming. 



Experiment 4-4- — Gas, 87 per cent of acetylene and 13 per 

 cent of nitrogen. The nitrogen was collected over an alka- 

 line solution of pyrogallic acid to absorb traces of oxygen, and 

 then was mixed with the acetylene over a solution of ferrous 

 sulphate in order to free the gases from possible traces of 

 ammonia. As the bomb leaked after the explosion, it was 

 only possible to determine approximately the ratio between the 



