664 Browning and Scott — Separation of Germanium. 



nected through a wash bottle with a carbon dioxide 

 generator, so that the gas could be used to facilitate the 

 boiling of the liquid, the distillation of the volatile chlor- 

 ide and finally aid in the removal of any chlorine which 

 might result from the action of the hydrochloric acid upon 

 the excess of chromate present. 



In this flask the material, consisting of a mixture of 

 arsenious oxide and germanium oxide, was placed and in 

 our experiments about 5 cm 3 of a 10 per cent solution of 

 potassium dichr ornate, together with a few drops of 

 sulphuric acid. This mixture was then warmed for about 

 a minute when the oxide dissolved and the arsenious acid 

 was oxidized to arsenic acid. About 10 cm 3 of strong 

 hydrochloric acid was added and the distillation was 

 made in a current of carbon dioxide until about one half 

 of the liquid was distilled, and the current of carbon 

 dioxide was continued until the liquid in the distillation 

 flask was cool. 



The distillate was then tested by hydrogen sulphide to 

 detect the presence of the yellow As 2 S 3 , or the white GeS 2 . 

 The results follow in the Table. 



As 2 3 



present 



grm. 



(1) 0-0500 



(2) 0-2000 



(3) 0-5000 



(4) 0-3000 



(5) 0-3000 



(6) 0-2000 



(7) 0-2500 



(8) 



(9) ...... 



(10) 



(11) 0-1000 



(12) 01000 



Ge0 2 



present 



grm. 



0-0050 



0-0005 



00010 

 0-0005 



Table I. 



10 Strong 



K 2 Cr 2 7 HC1 

 present present 



cnr 



10 



10 



10 



10 



10 



3 



6 



5 



6 



10 



10 



10 



Water 



present 



Result on 



treating 



distillate 



with H 2 



No ppt. 

 No ppt. 



As 2 S 3 

 As 2 S 3 



-A_S 2 ^g 



No ppt. 



No ppt. 



No ppt, 



GeS 2 



GeS, 



GeS; 



GeS 2 



Experiments 1-7 were carried out with varying amounts 

 of arsenious oxide only, to determine the amount of 

 arsenic which would be oxidized by about (J-5 grm. of 

 potassium dichromate. It was found that 0*2500 grm. 

 of arsenious oxide could be successfully oxidized by this 



