374 ELEMENTARY CHEMICAL MICROSCOPY 



Group HI. Non- volatile with sulphuric acid. 



Arsenate. 



Arsenite. 



Chromate, bichromate. 



Manganate. 



Permanganate. 



Phosphate. 



Sulphate. 



The separation by the above method may be carried out as 

 described under Distillation, page 245. 



ACETATES. 



a. With Silver Nitrate in concentrated, approximately neutral 

 solution, pearly scale-like crystals of silver acetate are obtained. 

 Later these develop into long thin prisms with more or less 

 Irregular sides and ends. Those in which six edges are de- 

 veloped give terminal angles a trifle over 90 degrees, and extinc- 

 tion almost parallel with their length (extinction angle 8 degrees). 

 To confirm the test distil a portion acidified with phosphoric 

 acid. In the absence of phosphoric acid, sulphuric acid may 

 be employed. 



b. With Mercurous Nitrate added to concentrated solutions. 

 Colorless plates and prisms; the thin six-sided prisms have their 

 terminal angles equal to 100 degrees and exhibit parallel ex- 

 tinction. 



c. With Sodium Chloride and Uranyl Nitrate in approximately 

 neutral solutions. Sodium uranyl acetate is obtained. See 

 Sodium, Method A, page 274. Add the uranyl nitrate to the 

 drop of unknown, and draw this solution across the dry film of 

 sodium chloride. 



ARSENATES. 



a. With Silver Nitrate. See Silver, page 337 ; Arsenic, page 351 . 



b. With Zinc Acetate and Ammonium Chloride in Ammoniacal 

 Solution. See Magnesium, page 306. 



ARSENITES. 



a. With Silver Nitrate. See Arsenic, page 351. 



