32 



VIVENCIO DEL ROSARIO. 



If n represents the number of cubic centimeters of ^ iodine solution 

 used, then : 



0.0127nM^ nM 

 2X127 "20,000 



From these constants the author has calculated the following factors: 

 Formaldehyde 1X0.11827 



Acetaldehyde 1X0.17348 



Benzaldehyde 1X0.41788 



Vanillin 1X0.59923 



My results are as follows : 



In a preliminary determination 0.0009 gram of aldehyde in 50 cubic 

 centimeters of 50 per cent alcohol gave : 



I 



II 

 III 

 Average, 



Aldehyde. 



0.0008401 



0.0009450 



0.0009450 



0.00091 



Table I. — Determination of known amounts of acetaldehyde 



N 



BLANK, 20 CUBIC CENTIMETER KHS0 3 



! ■ .;n . 1 i.i' 11 i.r ~- IODINE (0.9533). 



Cubic cen- 

 timeters of 

 aldehyde 

 solution. 



Grams of 



aldehyde 



used. 



Cubic cen- 

 timeters of 



iodine jq- 



Grams of 



aldehyde 



found. 



Percent- 

 age. 



5 



10 

 15 

 20 

 25 

 30 

 35 

 40 

 45 

 50 



.0045 

 .0090 

 .0135 

 .0180 

 .0225 

 .0270 

 .0315 

 .0360 

 .0405 

 . 0450 



40.15 

 38.00 

 35. 85 

 33.80 

 31.50 

 29.55 

 27. 35 

 25.15 

 22.95 

 20.70 



. 00451 

 . 00903 

 . 01355 

 . 01784 

 . 02268 

 . 02677 

 . 03139 

 . 03600 

 . 04063 

 . 04536 



100. 22 



100.34 



100. 37 



99.11 



100.80 



99.14 



99. 65 



100. 00 



100. 24 



100. 80 



Table II. 



20 CUBIC CENTIMETER KHSO s = 38.15 CUBIC CENTIMETER ~ (1.0146). 





5 



.0045 



36.15 



. 00447 



99.36 



10 



.0090 



34.10 



. 00905 



100. 61 



15 



.0135 



32.10 



. Q1353 



100. 22 



20 



.0180 



30.15 



. 01788 



99.33 



25 



.0225 



28.00 



. 02269 



100.84 



30 



.0270 



26.00 



.02716 



100. 59 



35 



.0315 



24.00 



. 03163 



100.41 



40 



.0360 



21.90 



. 03633 



100. 91 



45 



.0405 



19.95 



. 04069 



100.46 



50 



.0450 



17.95 



. 04516 



100. 33 



From these results it is evident that the volumetric method as out- 

 lined will undoubtedly be useful to the commercial analytical chemist. 



