DECOMPOSITION OE HXDRIODIC ACID. CREIGHTON. 



13 



The curves for these numbers are similar in form to those 

 for 24C. The only difference between the behaviour at this 

 temperature and that at 24C. is that at the former the decom- 

 position of the solution is much slower, and the equilibrium 

 values consequently much longer in being reached. The effect 

 of radium is again apparently only to increase the action in 

 degree, but not to change it in type. Here, too, as at 24C., 

 there is probably no third product being formed from the iodine. 

 The reaction was next observed at 36C., and the following 

 table shows the results obtained : 



TABLE V. 



No. of cc. of j-^ Na 2 S 2 O 3 solution required in titration 

 when the decomposition of hydriodic acid solution takes 

 place in the presence of 



The curves formed from these numbers are given in figure 2. 



