Gooch and Blumenthal — Use of Selenic Acid. 



61 







T 



ABLE Y. 







The Evolution of Bromine by Sulphuric 



Acid and Sodium Selenate. 



Br taken 



Na 2 Se0 4 



H 2 S0 4 



Final 



Br 





as KBr 



taken 



(1:1) 



volume 



found 



Error 



grm. 



grm. 



grm. 



cm 3 . 



grm. 



grm. 



0-1041 



1-2 



12 



15-16 



0-1029 



— 0-0012 



0*1041 



12 



12 



13-14 



0-1033 



— 0-0008 



00694 



1-2 



12 



17-18 



0-0686 



— 0-0008 



0*0694 



1-2 



12 



16-17 



0-0692 



— 0-0002 



0-0694 



1-2 



12 



16-17 



0-0691 



— 0-0003 



00694 



0*6 



12 



12-13 



0-0691 



— 0-0003 



0*0694 



0-6 



6 



11-12 



0-0691 



— 0-0003 



0-0694 



1-8 



3 



12-13 



0-0689 



— 0-0005 



0-0694 



1-8 



3 



12 



0-0691 



— 0-0003 



0-0694 



1-8 



3 



12 



0-0689 



— 0-0005 



0-0694 



1-8 



3 



10 



0-0691 



— 0-0003 



0-0694 



0-6 



3 



11-12 



0-0669 



— 0-0025 



tions of the bromine in potassium bromide associated with 

 sodium chloride, made under these conditions, are recorded in 

 Table VI. In these determinations the relay flask (II) was 

 used, charged with l cm3 to 2 cm3 of sulphuric acid (1 : 1), 0*2 



grm. to 0'3 grm. 

 water. 



of sodium selenate, and 10 cm3 to 15 cm3 of 







Table VI. 









Determination of Bromine by Selenate- Sulphuric Acid Process. 



Br taken 

 as KBr 



NaCl 

 taken 



Na 2 Se0 4 

 taken 

 I II 



H 2 S0 4 

 (1:1) 

 taken 

 I II 



Final 

 volume 



I 



Br 

 found 



Error 



grm. 



grm. 



grm. grm. 



cm 3 



cm 3 



cm 3 



grm. 



grm. 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



14 



0-0683 



— 0-0011* 



0-0694 



0*0500 



1*8 0-2-0-3 



3 



1-2 



13-14 



0-0690 



— 0-0004 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



13-14 



0-0690 



— 0-0004 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



12-13 



0-0693 



—o-oooi 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



12-13 



0-0693 



— O'OOOl 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



11 



0-0692 



— 00002 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



11 



0-0683 



— O'OOll 



0-0694 



0-0500 



1-8 0-2-0-3 



3 



1-2 



10 



0-0692 



— 0-0002 



C0 2 was passed for a considerable time after cooling. 



The average error in these determinations is 0*0004 grm. in 

 terms of bromine. 



According to the procedure which we have found to be 

 effective for the amounts of material dealt with, the haloid salt 

 is introduced into the reaction flask with 30 cm3 of water. 

 Selenic acid, 5 cm3 of 40 per cent acid, or the mixture of 1-8 



