IN AQUEOUS SOLUTION, AND THE EXISTENCE OF COMPLEX IONS. 
1 ;i5 
it does ; this w(.)uld mean, eitliev that the Ba ion has its velocity diminished more 
than the anion in solution of the chloride but not in the nitrate, or, that the NOg ion 
is diminished in velocity in the barium salt, but not in the potassium salt. Further, 
the variation in for potassium sulphate points to the fact that the potassium ion is 
retarded more than the sulphate, hut not more than the chloride. Any of these con¬ 
clusions are of course possible, but improbable, and the more so since all the facts are 
far more simply explained by the supposition that complex ions exist in certain salt 
solutions. 
The variation in p with N, which is found by direct measurement in aqueous 
solution, seems to point to the correctness of the assumption of a variation in u and i’. 
But for this class of salts it has been demonstrated for a few cases, and is probably 
true for all, that a change in concentration of the solution occurs within the anion 
boundary. Such a change does not occur with potassium chloride, and it is not clear 
how it can be brought about in a system containing only simple ions. And here 
again a more reasonable explanation is afforded by the theory of complex ions. 
The form of the equation given by Masson for the relation between current and 
margin velocity is not altered by supposing a variation in u and r, hence no explana¬ 
tion is aftbrded liy this assumption of the divergence from unity of the ratio of the 
current as measured liv the o-alvanometer to that calculated from the observed 
*j 
velocities. 
The difficulty in assigning values to the specific ionic velocities finds here, also, a 
possible explanation. For a given solution the conductivity is X = e (-■ {u + r), where 
e is the quantity of electricity carried liy one monad ion, and u, v, and c have the 
same signification as before. The molecular conductivity p, = — e ~^u v), where 
n is the total concentration of the solution. 
For infinite dilution, c = n and w'here v^ and 
velocities at infinite dilution. Hence — = A . d—Ad_. Here 
a -j- Tji 
ionic to total concentration, or the coefficient of ionization. 
V 
X 
C 
/I 
are the specific 
= the ratio of 
Therefi )re 
and since 
» -f ’ 
p^= + rq) therefore rr = 
_ 
e(a -f r) ’ 
or the coefficient of ionization is given by the ratio of the molecular conductivity to 
the product of e into the sum of the specific velocities at the same concentration, and 
is only equal to when {u + v) = + Vm). 
From what has been already said, the probability is that if u and ?? change, 
u + V is less than (?q + and hence the real value of x is greater than ^ . 
