Properties of Aqueous Solutions to their State of Ionization. 107 



* 



Ionization-Coefficients {a). 



HCl 

 j»oo=3500. 



NaCl 

 ,•.=1090. 



iK 2 C0 3 



^;=moo. 



JH 2 S0 4 . 

 /*«, =13700. 



AgN0 3 . 

 /• oo =1090. 



o-oi 



•976 



•934 



•773 



•772 



•933 



01 



•927 



•840 



•628 



•563 



•794 



0-5 



•862 



•735 



•520 



•513 



•668 



10 



•794 



•675 



•471 



•492 



•582 



The approximate constancy holds in the case of HCl and 

 JK 2 C0 3 , because /jl^ for HCl being more than twice as great 



'2 



5 for 



:KoC0 3 , a. for the latter falls off nearly twice as 

 rapidly as for the former. In the case of AgN0 3 and NaCl 

 there is no approximation to constancy, because the values of 

 fju^ being nearly equal, the rates at which a varies with n are 

 very unequal, 



The Independence of the Contributions made to the Value of 

 a Property by the Free Ions. 



The constant I for a salt ap will, according to the dissocia- 

 tion conception, be composed additively of two parts, l a and 

 l p , pertaining to the ions a and p respectively, and these con- 

 stants I a and l p will be characteristic of the ions and will not 

 depend upon the salt from which they have been dissociated. 

 A certain amount of evidence has been accumulated which 

 may be said to point in this direction. In the case of several 

 properties it has been shown that for solutions of considerable 

 dilution, the difference between the values of the property for 

 solutions of two salts having a common ion and the same 

 molecular concentration, is independent of what the common 

 ion may be ; and the value of the difference divided by the 

 numbers of gramme-equivalents per litre of the salts in solution 

 has been taken to be approximately the difference between 

 the constants l a and J P . Results of this kind have been obtained 

 by Yalson and Bender for density and refracting power, by 

 Kohlrausch for electrical conductivity, by Eaoult for the 

 depression of the freezing-point, by Traube* for the change 



* Ztschr. anorgan. Chemie, iii. (1892), p. 1. 



