34 UNIVERSITY OF COLORADO 



neck of the flask reaching to within about J inch from the bottom. 

 The flask is set on a sand bath 4 inches in diameter, so that the 

 naked flame shall not play on the sides of the flask, so avoiding 

 the raising of the temperature at any spot above that desired. Al- 

 low the outlet of the condenser to dip about £ inch into about 40 

 cc. of cold water in a No. 1 beaker. 



Heat the flask gradually until the thermometer reads 115° C, 

 then remove the stopper and add 10 to 25 cc. strong HC1, collecting 

 the second distillate in water as before. 



The distillate is poured into a No. 3 beaker, made alkaline with 

 NH 4 OH, just acidified with HC1, cooled, about 8 grams of bi-carbon- 

 ate of soda and some starch solution added, and titrated with stand 

 ard iodine solution. 



Antimony may now be determined after removing the stopper 

 containing the thermometer and inserting another through which 

 is a glass tube reaching nearly to the bottom of the flask and con- 

 nected with a HC1 gas generator. This generator contains HC1, 

 into which H 2 S0 4 is allowed to drop from a separatory funnel at 

 the rate of about two drops per second. 



The condenser is sealed with cold water as for the arsenic dis- 

 tillation and heat is applied to the flask until the mass in the flask 

 becomes about dry. Do not heat to a much higher point, since cop- 

 per chloride is liable to come over. Remove the beaker containing 

 the distillate, add a little tartaric acid, almost neutralize with am- 

 monia and pass in H 2 S gas. If the orange antimony sulphide ppt. 

 shows up, put under the condenser other beakers of water as seals, 

 keeping up the heating and passing in of the HC1 gas until no ppt. 

 is formed with H 2 S. 



Filter the sulphide of antimony into a tared Gooch crucible, 

 heat in an air bath at 255° C. for one hour and weigh. The weight 

 multiplied by 71.40 will give the amount of antimony. 



It takes about 15 minutes each for the arsenic and antimony 

 distillations. In the distillation some uncombined sulphur comes 

 over, but does not affect the results. No sulphurous acid or H,S 

 will be found with the arsenious chloride distillate. Antimonous 

 chloride can not be titrated, owing to other decompositions from 

 the high temperatures required to distill it. 



The solutions required are: Cupric Chloride — Dissolve 300 

 grams of pure cupric chloride crystals in 1 litre of HC1. This so- 

 lution is mixed with 1 litre of a solution of zinc chloride, which 



