NATURE OF SOLUTION. 615 
Stronger solutions were now tried, and the numbers below show that the 
solubility increases rapidly with the concentration of the acid. 
HCl (sp. gr. 1:080). 
& p Na,S,0, a 
—58 763°7 59-4 64596 
—4:8 60-2 65466 
338 592 64378 
Bae! 580 63073 
£3 56'1 61007 
2-5 516 56113 
6°8 A5‘1 49045 
155. 38:1 41433 
26:0 29°5 3:2080 
31-0 21-2 ° 93054 
35°6 16°7 18161 
39°6 13:9 15116 
45:2 12°3 13-376 
1 c.c.=0:01243 iodine. 
HCl (sp. gr. 1°125). 
i p Na,S,0, a 
—10°0 763°7 80:9 8:7976 
— 50 83:1 9:0369 
— 22 ; 745 * 81017 
+ 08 65:5 71229 
10:0 57-0 61843 
20°7 43:8 47631 
1 ¢.c.=0°012438 em. iodine. 
No chlorine hydrate was formed. 
It will be noticed that the points of maximum solubility occur at lower 
temperatures with the stronger solutions, and if the summits of the curves be 
connected so as to form a curve of maxima the latter is found to be very steep, 
and it was thought that at still lower temperatures chlorine gas might be got 
to combine with dry hydrochloric acid to form a perchloride of hydrogen. 
The experiment was tried by passing the dry gases into a flask, cooled down to 
about —10°, but no result was obtained. The high solubility of chlorine in 
hydrochloric acid solutions certainly points to the formation of a perchloride, 
and it is probable that under increased pressure the two gases would combine 
at low temperatures. 
Mixed Chlorides.—It ‘is well known that when chlorine is passed into a 
solution of lead chloride and sodium chloride it is absorbed in large quantity, 
and a perchloride of lead is formed. The chloride by itself does not combine 
VOL. XXX. PART III. DD 
