g 



8CHLUNDT SPEED OP THE LIBERATION OF IODINE 33 



CONCLUSIONS. 



The foregoing results lead to the following conclusions: 



1. The speed of the reaction is influenced to a marked de- 

 ree by the temperature, the speed increasing with the 



rise of temperature. 



2. The presence in the mixture of an excess of one or 

 more of the components increases the speed. The effect 

 of an excess of potassium iodide is about the same as an 

 equivalent excess of potassium chlorate. But a corre- 

 sponding excess of acid causes a greater increase of speed. 



3. Other things being equal the speed of the reaction is 

 modified by degree of concentration of the mixtures, the 

 speed increasing with the concentration. 



4. To obtain the complete reduction of potassium chlo- 

 rate by potassium iodide and hydrochloric acid in a com- 

 paratively short time, the solutions must be concentrated, 

 there must be present quite an excess of both potassium 

 iodide and hydrochloric acid, and the mixture must be 

 strongly heated. 



5. The presence of an excess of the ordinary inorganic 

 acids accelerates the reaction. Assuming their respective 

 influences as indicating their relative strengths,' the results 

 on acceleration show the following order of strength: 

 (1) hydrobromic, (2) hydrochloric, (3) nitric, and (4) sul- 

 phuric. 



6. Organic acids and boric acid do not increase the 

 speed. 



This work was undertaken at the suggestion of Mr. 

 Louis Kahlenberg, instructor in chemistry at the Univer- 

 sity of Wisconsin, and was carried out under his immediate 

 direction. For the kindly interest he has always taken in 

 my work I here desire to express my sincere thanks. 



1 These acids are arranged in the same order by Ostwald, who investigated the influence 

 of their presence on the speed of the reduction of bromic acid bj' hydriodic acid. 

 Zeitsch. physik. Chem., 2. p. 135. (1888) ■ 



