XI, A, 1 Heise and Aguilar: Oxygen Consumption of Waters 41 



EFFECT OF CHLORIDES 



As chlorides have a marked effect on permanganate digestion 

 at boiling temperature, and as the typical Philippine waters 

 submitted to this laboratory for analysis are generally high in 

 chlorine, it seemed worth while to us to make accurate measure- 

 ments on waters of varying chloride content. 



The determinations were made with the ordinary distilled 

 water of the laboratory, a water which still contained a small 

 amount of organic matter. The same water was used in mak- 

 ing up a standard solution of fused sodium chloride, portions 

 of which were then diluted with varying amounts of water to 

 give samples of the desired concentrations. The determinations 

 of oxygen consumption were made in the usual manner, using 

 100 cubic centimeter samples and digesting at 100° C. for thirty 

 minutes. 



The analytical results are recorded in Table V. 



Table V. — Effect of dissolved chlorides on determinations of oxygen- 

 consuming capacity. 



[Sample, 100 cubic centimeters ; digested for thirty minutes at 100° C] 

 SERIES 1. 



Chlorine 



content 



(parts per 



million). 



Perman- 

 ganate 

 required. 



Difference in 

 perman- 

 ganate 

 required. 



Error intro- 

 duced in 

 terms of 

 oxygen con- 

 sumed (parts 

 per million). 





 5 



10 

 20 

 60 

 100 



cc. 

 1.14 

 1.20 

 1.22 

 1.33 

 1.36 

 1.40 



cc. 





0.06 

 0.08 

 0.19 

 0.22 

 0.26 



0.01 

 0.03 

 0.14 

 0.17 

 0.21 



SERIES 2. 



0.0 

 43.3 



0.56 

 0.73 







0.17 



0.16 



6B.0 



0.85 



0.29 



0.27 



77.0 



0.85 



0.29 



0.27 



93.4 



0.94 



0.38 



0.37 



118.3 



1.02 



0.46 



0.44 



161.0 



1.10 



0.54 



0.52 



197.0 



0.90 



0.34 



0.32 



253.0 



1.13 



0.57 



0.55 



355.0 



1.32 



0.76 



0.73 



442.6 



1.97 



1.41 



1.37 



B22.0 



1.78 



1.22 



1.20 



710.0 



2.07 



1.51 



1.49 



887.5 



3.62 



3.06 



2.99 



1.183.0 



4.80 



4.24 



4.14 



1.775.0 



4.70 



4.14 



4.06 



3.550.0 



7.11 



6.55 



6.41 



