56 



PHYSICAL CHEMISTRY 



the concentration of the ions and HA of the undissociated mole- 

 cules of the acid. 



The dissociation constants of some weak acids and substances 



which dissociate traces of H" 

 from Scudder, 191 5) : 



are as follows at 25 (mostly 



The temperature coefficient for the dissociation of acids and 

 bases is usually small. 



In case of C0 2 and NH 3 , the above figures show only the 

 apparent dissociation constants. The real acid and base are 

 H 2 CO s and NH 4 OH, but the concentration of these is unknown. 

 According to the investigations of Thiel and Strohecker (1914) 

 the dissociation constant of H 2 C0 3 is greater than that of formic 

 acid. 



