Phosphorous, Hypophosphoric and Phosphoric Acids. 99 





Table VI. 







lodonit 



"Aric Estimat 



ion of Phosp, 



horous Acid. 





Iodine solution 



1049 N/10. 



Thiosulphate 



solution 1-00S N/10. 







Na.SA 







H,P0 3 



Iodine 



solution 



H 3 P0 3 



Found 



taken 



solution 



required 



found 



% 



cm 3 grin. 



em 3 



cm" 



grm. 





15 005387 



45-00 



33-75 



005411 



100-45 



20 007182 



4500 



29-37 



007223 



100-57 



25 0-08978 



45-00 



2503 



009018 



100-44 



30 0-1077 



4500 



20-68 



0-1082 



100-46 



35 01257 



45-00 



16-35 



01261 



100-32 



40 01436 



4500 



11-93 



01443 



100-49 



Beagents used in each determination. 

 cm 3 of glacial acetic acid. 



11 grams of Na 2 HP0 1 .12H 2 0. 



phosphoric acid, or is the result of an error in the stand- 

 ard of one of the N/10 solutions, we are unable to say. 

 On account of lack of time this point was not further 

 investigated. 



Table VII is a study of the effect produced by the 

 presence of a hypophosphate upon such analyses. The 

 exact standard of the phosphorous acid solution was 

 unknown. Its equivalent reducing power was approxi- 



Table VII. 

 Estimation of Phosphorous Acid in Presence of Eypophosphoric Acid. 



Phosphorous acid solution approximately N/50. Hypophosphate solution 

 approximately N/20. Iodine 1022 N/50. Thiosulphate 1006 N/50. 



Error 



H 3 P0 3 



Na^HPoOc 



Iodine 



Na 2 S 2 3 



per 10 cm 3 of 



H3PO3 



taken 



taken 



taken 



required hypophosphate 



found 



em 3 



cm 3 



cm 3 



cm 3 



cm 3 of I, 



grm. 



2500 





45-00 



21-38 





002009 



25-00 



l'o'io 



4500 



21-26 



042 



002019 



3000 





45-00 



16-58 





0-02405 



3000 



9-90 



4500 



16-35 



0-23 



002424 



3500 





4500 



11-61 





0-02815 



3500 



20-66 



45-00 

 45-00 



11-43 

 45-70 



0-09 



0-02831 



.... 



10-66 



45-00 



45-58 



012 





Beagents used in each determination. 25 cm 3 of an 11% solution of 

 Na 2 HPO J .12H 2 0. 5 cm 3 of 42% H 3 P0 4 solution. 10 cm 3 of 10% KI 

 solution. 



mately N/50, while that of the sodium acid hypophos- 

 phate solution, as determined by the permanganate 

 method, was a little over N/20. 



In this series a slight reduction of the iodine by the 



