266 J. SAKURAI; 



The ' strength ' of amidosul phonic acid may be judged of from 

 the degree of its dissociation, fi^l^—m. The following table, in 

 which 100 times this ratio is calculated, shows that amidosulphonic 



acid is already dissociated to the extent of 71) % in a — y K solution 

 and that the degree of dissociation attains 98 % m a -jk^ ^" solution : 



Amidosulphonic acid ( t u x =873.97). 



v = 32 64 128 256 512 1024 



^„ = 295.78. 324.86 341.87 359.20 361.95 366.4(3 

 100 m = 79.09 86.87 91.42 96.04 96.79 97.99. 



Amidosulphonic acid may, therefore, be ranked among the strong 

 mineral acids, being nearly comparable with iodic acid, as may be seen 

 from the following numbers : — 



100 m. 



In its constitution, amidosulphonic acid is sulphurous acid in 

 which the H directly combined with sulphur has been replaced by 

 the group NH 2 : 



Sulphurous acid. Amidosulphonic acid. 



Now, it is evident from the determinations of Ostwald (Jour. 

 prakt. Chem., 32, 314 [1885]) and of Barth (Zeit, physih Chem., 



