140 Van Name — Estimation of Copper as Sulphocyanide 



Table I (continued). 

 Final volume 500 cm3 . 







Bi 











Calcu- 









taken as 





Tartaric 



HNH 4 S0 3 



Cu 2 S 2 (CN) 2 



lated 





Cu taken. 



BiCU + HCl. 



HC1 



acid. 



sat. sol. 



found. 



as Cu. 



Error. 





grm. 



grm. 



cm 3 . 



grm. 



cm 3 . 



grm. 



grm. 



grm. 



14. 



•3144 



0-5 



20 





10 



•6534 



•3415 



+ •0271 



15. 



a 



0-4 



25 





a 



•5933 



•3101 



— •0043 



16. 



u 



0-2 



20 





5 



•5932 



•3101 



— •0043 



17. 



u 



0*2 



a 





10 



•6014 



•3143 



— •0001 



18. 



a 



o-i 



a 





a 



•5977 



•3124 



— •0020 



19. 



tt 



0-05 



a 





a 



•5998 



•3135 



— •0009 











Final volume 300 cm3 . 









20. 



ti 



0-5 



10 



1 



5 



•6007 



•3139 



— •0005 



21. 



a 



0-4 



a 



a 



a 



•6018 



•3145 



+ •0001 



22. 



a 



0-2 



a 



a 



a 



•6003 



•3137 



— •0007 



23. 



a 



o-i 



7 



a 



a 



•6033 



•3153 



+ •0009 



24. 



•3163 



o-i 



10 



a 



a 



•6033 



°3153 



— •0010 



25. 



a 



o-i 



8 



a 



a 



•6056 



•3165 



+ •0002 



acid, using no tartaric acid. In experiment 14 the free acid 

 present during the precipitation of the copper did not suffice 

 to hold up all the bismuth. In the others, with the exception 

 of no. 17, the acid prevented the complete precipitation of 

 the copper. 



For experiments 20 to 25 the quantities of hydrochloric 

 acid required were materially diminished by the addition of 

 tartaric acid, and by reducing the total volume from 500 cm3 to 

 300 cm3 . The quantities of tartaric and hydrochloric acids 

 required were previously determined by a series of blank tests 

 and both kept as low as possible. 



The results fall fairly near the theory but average a trifle 

 low, and the filtrates of all, even those which show positive 

 errors, gave decided tests for copper when concentrated and 

 treated with potassium ferrocyanide. Moreover, a slight varia- 

 tion in the conditions would allow some of the bismuth to be 

 precipitated. The results therefore are hardly satisfactory. 



Table I (continued). 

 Final volume 500 cm3 . 





Sb 













Calcu- 







taken 



as 





Tartaric 



HNH4SO3 



Cu 2 S 2 (CN) 2 



lated 





Cu taken. 



SbCl 3 + 



H01. 



HC1. 



acid. 



sat. sol. 



found. 



as Cu. 



Error. 



grm. 



grm. 





cm 3 . 



grm. 



cm 3 . 



grm. 



grm. 



grm. 



26. -3163 



0-5 





10 



2 



5 



•6024 



•3148 



— •0015 



27. " 



0-4 





8 



a 



tt 



•6043 



•3158 



— •0005 



28. " 



0-3 





a 



a 



a 



•6044 



•3159 



— •0004 



29. " 



0'5 





5 



tt 



a 



•6046 



•3160 



— •0003 



30. " 



0'4 





tt 



a 



a 



•6054 



•3164 



+ •0001 



31. " 



0-2 





a . 



a 



a 



•6058 



•3166 



+ •0003 





