198 Drushel — Volumetric Estimation of Lanthanum. 



acetic acid. The precipitate is thoroughly stirred and allowed 

 to settle. It is then filtered through a perforated crucible 

 fitted with an asbestos felt. After thoroughly washing with 

 water the crucible and precipitate are placed in a beaker with 

 100 to 300 cm3 of water and 10 to 30 em3 of (1:4) sulphuric acid. 

 The contents of the beaker are heated nearly to boiling and at 

 once titrated to color with standard potassium permanganate. 

 The filtrate is similarly titrated as a check on the titration of 

 the precipitate. The lanthanum is calculated as La 2 3 from 

 the two titrations. The mean of the two closely agreeing 

 values thus obtained is taken. 



The solution of ammonium lanthanum nitrate used in this 

 work was standardized by evaporating measured portions to 

 dryness and carefully igniting the residue to constant weight. 



Table of Results. 





[Lanthanum 





138-9] 







La 2 3 taken as 



La 2 3 



found. 









the double nitrate 



Precipitate 



Filtrate 



Average 



Error 





grain. 



grain. 



grain. 



gram. 



gram. 



1. 



0-0148 



0-0152 



0-0144 



0-0148 



o-oooo ± 



2. 



0-0148 



0-0149 



0-0139 



0-0144 



0-0004 — 



3. 



0-0296 



0-0302 



0-0291 



0-0296 



0.0000 + 



4. 



0-0296 



0-0302 



0-0293 



0-0297 



o-oooi + 



5. 



0-0592 



0-0599 



0-0586 



0593 



0-0001 + 



6. 



0-0592 



0-0598 



0-0585 



0-0592 



0*0000 + 



7. 



0-1184 



0-1191 



0-1179 



0-1185 



0-0001 + 



8. 



0-1184 



0-1191 



0-1182 



0-1187 



0-0003 + 



9. 



0-2368 



0-2376 



0-2362 



0-2369 



0-0001 + 



10. 



0-0148 



0-0149 



0-0145 



0-0147 



o-oooi — 



11. 



0-0148 



0-0150 



0-0147 



0-0148 



0-0000 + 



12. 



0-0296 



0-0298 



0-0293 



0-0295 



o-oooi — 



13. 



0-0592 



0-0596 



0-0589 



0-0593 



0-0001 + 



14. 



0-1184 



0-1190 



0-1182 



0-1186 



0-0002 + 



15. 



0-1036 



0-1040 



0-1029 



0-1035 



o-oooi — 



to 9 ammonium oxalate was used in making 



In experiments 1 

 the precipitation, in 10 to 15 oxalic acid was used 



In conclusion the author acknowledges his indebtedness to 

 Prof. Philip E. Browning for helpful suggestions during the 

 progress of the work. 



