374 



5 CCS. of the hydroxyammonium chloride solution, equivalent to 

 9.9 CCS. of the iodine solution, were used in each case, and diluted, 

 to the extent stated in the table, by addition, after the water 

 when this was also used, first of the acid and then of the same 

 volume of the carbonate. A little bicarbonate was added as usual 

 during: titration. 



Acid and 

 carbonate, 

 CCS. of each. 



Total vols, of the dil^ 5 ces. of hydroxy"^ chlor. 



15 



25 



35 



45 



55 



65 



75 



85 



Ces, of iodine solution required. 







9.95 



10.1 



10.2 



10.3 



10.25 



10.45 



10.5 



lO.G 



5 



10.7 



10.7 



10.6 



— 



11.2 



— 



11.2 



— 



10 





11.2 



— 



11.4 



— 



11.7 





— 



15 







11.0 



— 



11.2 



— 



11.7 



— 



20 









11.7 



— 



12.0 



— 



— 



25 











11.35 



— 



12.0 



— 



30 













12.0 



12.3 



— 



Blank tests showed that the diluents alone decolourised no 

 iodine. 



A corresponding series of trials were made with sulphuric acid in 

 place of hydrochloric acid. The solutions used were:-^ 



Hydroxyammonium chloride 



Iodine (as before) 



Sodium carbonate (as befors) 

 Sulphuric acid 



6.6492 grams per liter, 

 12.6238 „ „ „ 

 96.3075 „ 

 89.0409 „ „ „ 



5 CCS. of the hydroxyammonium chloride, equivalent to 9.65 

 CCS. of iodine solution, were used in each case, and diluted on the 

 same plan as before to the extent shown in the table. 



