rmination of lodiru in II<tl<>i(l Salts. 

 simm yky of Series I. 



195 



H E 









Per com of 





[1:1]. 



Final 



vol 



nine. 



strong lljSi), 



XaCl. 









by volume. 





10 cm 



•JO 



■in ■ 



1 







•20 



40 







26 



1 urni. 



30 



80 





) 







10 



20 





I 





\ and [ 

 I 0-8 ) 



20 



40 





[ 



25 



30 







J 







30 







333 



\ °* 5 ) 



(i-o) 













Mian loss of 

 As,0 3 . 



0-000(5 

 00005 

 0-0010 

 0-0003 

 0*0005 

 0-0005 



0008 

 0-0019 

 0-0029 



err— 



Number of 

 determina- 

 tion. 



3 



It appears in these results that there is some loss of arsenic 

 in nearly every ease within the limits of our experimentation, 



the amount of volatilization increasing with the ratio of sul- 

 phuric acid to the entire volume when the quantity of chloride 

 present is constant, and likewise with the amount of chloride 

 when the ratio of the acid to the total liquid is constant. 



The effect of increasing the amount of chloride is naturally 

 accounted for by the "mass action'' of the hydrochloric acid 

 thus liberated upon the arsenious oxide in solution ; that it is the 

 proportion, and not the absolute amount, of sulphuric acid which 

 determines the degree of volatility of the arsenic is explicable 

 upon the assumption that the smallest quantity of sulphuric 

 acid employed is sufficient to liberate all the hydrochloric acid 

 (or, at least, nearly all), and that this, by its action on the arse- 

 nious oxide, forms the volatile chloride proportionately to the 

 amount of water removed bodily by concentration or withheld 

 from effective action by the attraction of the sulphuric acid. 



In extending this line of experimentation to cases involving 

 the action of hydrobromic acid upon arsenious oxide we found 

 it sufficient for our purpose to employ only the highest degree 

 of concentration recorded in the previous experiments and to 

 use 1 grm. of potassium bromide — an amount corresponding, 

 molecule for molecule, to about 0'5 grm. of sodium chloride. 

 The results, given in Series J, indicate that under these cir- 

 cumstances the loss of arsenic is inappreciable. 



Series J. 



H 2 S0 4 

 [1:1]. 



KBr. 





grm. 



20 cm 3 



1 



20 



1 



20 



1 



20 



1 



20 



1 



Final 

 volume. 



Per cent of 



strong Hs 2 S0 4 



by volume. 



30 cm 3 



30 



30* 



30 



30 



33-3 



333 

 333 

 33-3 

 33-3 



grm. 

 0-0495 

 00495 

 0-0495 

 0-0495 

 00495 



As 2 3 

 found. 



grm. 



00490 

 0-0493 

 00495 

 0-0495 

 0495 



Loss. Mean loss. 



grm. 

 00005 

 0-0002 

 0-0000 

 00000 

 00000 



1 



grm. 



y o-oooi- 



