1898-99.] Sulphuric Acid and Sulphates in Solution. 
515 
series of experiments with solutions of sulphuric acid and neutral 
sulphates. As it was interesting to know in how far the percen- 
tages of free acid calculated from his measurements agreed with 
mine, I have made use of a few of his numbers for that purpose. 
Only in the case of sodium sulphate and sulphuric acid has Trey 
made a long series of experiments, and few of these correspond to 
the solutions which I employed. I obtained, however, several 
values of this percentage, for solutions corresponding to mine, by 
graphic interpolation. These, as well as others calculated directly 
from Trey’s experimental results, are shown in the accompanying 
table, the figures obtained by interpolation being indicated by 
brackets. The agreement between the two series of numbers is 
even better than was to be expected. 
Percentage of Free Acid. 
h 2 so 4 
Na 2 S0 4 
Trey. 
Kay. 
0-35 + 
o-i 
(84-5) 
84-9 
0-2 
0-2 
63-7 
60‘6 (for K 9 S0 4 ) 
0-2 
o-i 
80-0 
80-9 
0-15 
0-15 
(67-7) 
67-4 (for K 2 S0 4 ) 
o-i 
o-i 
(72-7) 
73-2 
0-08 
0-08 
74-9 
(75-2) (for K 2 S0 4 ) 
The concentrations of the free acid, neutral and acid sulphates 
the various solutions were calcuh 
percentage of free acid in the same. 
in the various solutions were calculated as before from the 
Concentration of Na 2 S0 4 = 0‘l. 
h 2 so 4 
Free acid. 
Neutral sulphate. 
Acid sulphate. 
0-025 
0-01552 
0*0905 
0-00948 
0-05 
0-03363 
0-0836 
0-01637 
o-i 
0-07323 
0-0732 
0-02677 
0-2 
0-1618 
0-0618 
0-0382 
0-35 
0-2973 
0-0473 
0-0527 
The product of these concentrations and the undissociated pro- 
portions gives the concentrations of the undissociated portions of 
free acid, neutral sulphate and acid sulphate, viz.: — C^l-aj), 
C 2 (l - a 2 ) and C 3 (l - a 3 ). These are shown in the next table. 
Concentration of Na 2 SO 4 = 0'l. 
H 2 S0 4 C 1 (l - a x ) 
0-025 0-007015 
0-05 0-01534 
0-1 0-03391 
0-2 0-07606 
0-35 0-1442 
C 2 (l-a 2 ) C 3 ( 1 — a 3 ) 
0-02996 0-002180 
0-02911 0-003745 
0*02761 0-007093 
0*02583 0-01146 
0-02171 0-01776 
(1"«2) 
(l-«s) 
•452 
•331 
•230 
•456 
•348 
•241 
■463 
•377 
•265 
•475 
•418 
•300 
•485 
•459 
•337 
