200 ON THE ATOMIC WEIGHT OF CHLOEINE. 



air. We have confirmed these experiments with different strengths of hydrochloric 

 acid and found that practically no iodine was liberated in the oxygen free solutions 

 employed. 



Approximately equal volumes of iodine in potassium iodide solution were run into 

 small Erlenmeyer flasks X and Y from the calibrated burette B. The iodine in X 

 was then titrated by means of thiosulphate solution from burette A ; hydrochloric 

 acid of known strength was then added to Y and the titration immediately completed. 



The experiments were repeated several times with the addition of hydrochloric acid 

 of j concentration : 



EXPERIMENT I. 



120 cub. centims. of -^ concentrated HC1 were added to the solution in flask Y. 



Volumes of iodine in K 1 taken. 

 Burette B. Flask X, 25 04 cub. centims. Flask Y, 25 04 cub. centims. 



Volumes of thio required by above 

 Burette A. Flask X, 25-13 cub. centims. Flask Y, 25 16 cub. centims. 



EXPERIMENT II. 



120 cub. centims. of i concentrated HG1 were added to the solution in flask Y. 



Volumes of iodine in K 1 taken. 

 Burette B. Flask X, 25-08 cub. centims. Flask Y, 25-10 cub. centims. 



Volumes of thio required by above 

 Burette A. Flask X, 25-21 cub. centims. Flask Y, 25-20 cub. centims. 



EXPERIMENT III. 



120 cub. centims. of i concentrated HC1 were added to the solution in flask Y. 



Volumes of iodine in K 1 taken. 

 Burette B. Flask X, 25 23 cub. centims. Flask Y, 25 19 cub. centims. 



Volumes of thio required by above 

 Burette A. Flask X, 25 31 cub. centims. Flask Y, 25 29 cub. centims. 



EXPERIMENT IV. 



120 cub. centims. of i concentrated HC1 were added to the solution in flask Y. 



Volumes of iodine in K 1 taken. 

 Burette B. Flask X, 25-05 cub. centims. Flask Y, 25-06 cub. centims. 



Volumes of thio required by above 

 Burette A. Flask X, 25-14 cub. centims. Flask Y, 25 1 7 cub. centims. 



Since hydrochloric acid of ^ concentration has then no influence on the titration of 

 iodine in potassium iodide solution by sodium thiosulphate solution, we felt justified 

 in using, in our experiments, such volumes of water as never permitted of the acid 

 solution attaining a greater strength than j concentrated. 



